Duolingo English Test · Reading

Duolingo Fill in the Blanks Practice: Complete the Words (Read and Complete)

On the Duolingo English Test, "fill in the blanks" means completing words: you see the first half of a word and type the rest. It appears in two question types — one-word Fill in the Blanks and paragraph-length Read and Complete. Here is how both work, two original practice paragraphs with every answer explained, and the traps that cost the most points.

Rules from Duolingo's DET Question Guide (2026), read 3 October 2026. The practice paragraphs are written by LingoLeap, not taken from the test. LingoLeap is not affiliated with Duolingo.

The two "complete the words" question types

Duolingo Fill in the Blanks and Read and Complete compared
	Fill in the Blanks	Read and Complete
What you see	One sentence, one unfinished word	A paragraph with several unfinished words
Time	20 seconds	3 minutes
Questions per test	6–9	3–6
Scoring	Right or wrong; spelling must be correct	Each word scored on its own; spelling must be correct
Text types	Stories, coursebooks, news, personal writing, conversations	Fiction, news or textbook text
Subscore	Reading (adaptive)	Reading (adaptive)

Sources: Question Guide pp. 2–3; counts also in the help center. In Read and Complete, the title and the first and last sentences are complete, missing words are never side by side, and they are never names or acronyms.

Fill in the blanks practice test: two paragraphs

Set a 3-minute timer for each paragraph. Each underscore is one missing letter. Write the full words on paper, then open the answers.

Paragraph 1 · Expository (textbook style) · 9 words

Why Cities Plant Trees

On a hot summer afternoon, a street lined with trees can feel several degrees cooler than a street without them. This happens ¹bec____ leaves block direct ²sunl____ and release water into the air, which ³co___ the space around them. Trees also ⁴cl___ the air by trapping dust on their ⁵surf____, and their roots help the ⁶gro___ absorb rain during heavy ⁷sto___. For these ⁸rea____, many cities now set clear ⁹tar____ for the number of trees they want to plant each year. The challenge is keeping young trees alive long enough to grow.

Show answers and explanations

because → because. A reason follows (leaves block the sun), so you need a linking word of cause: bec- → because.
sunlight → sunlight. "block direct sun___" needs a noun; sunl- can only become sunlight.
cools → cools. The subject is "which" (= the process), so a third-person verb with -s: co- → cools. "cool" loses the point for grammar.
clean → clean. Trees remove dust from the air: cl- → clean. "clear the air" is an idiom about ending an argument, so it does not fit here.
surfaces → surfaces. After "their" you need a plural noun (leaves have many surfaces): surf- → surfaces.
ground → ground. Roots help the ___ absorb rain: gro- → ground. "grow" is a verb and does not fit after "the".
storms → storms. "heavy ___" + rain context: sto- → storms. The plural fits "during heavy" + general statement.
reasons → reasons. "For these ___" is a fixed phrase that needs a plural noun: rea- → reasons.
targets → targets. "set clear ___ for the number of trees": tar- → targets (a goal). Singular "target" would need "a".

Paragraph 2 · Narrative (story) · 9 words

The Last Train Home

Maya checked the station clock and realized she had missed the last train by four minutes. At ¹fi___ she felt angry with ²her____ for staying so long at the party. Then an ³eld____ man on the bench offered to ⁴sh___ a taxi, since he was ⁵trav_____ in the same ⁶dire_____. During the ride they ⁷disco_____ that they had grown up on the same small ⁸isl___, decades apart. He told her stories about the old harbor, and she promised to ⁹vi___ it that summer. By the time Maya got home, she was almost glad she had missed the train.

Show answers and explanations

first → first. "At ___" at the start of a story beat signals time order: fi- → first. The next sentence starts with "Then".
herself → herself. "angry with ___" + the subject is Maya, so a reflexive pronoun: her- → herself.
elderly → elderly. "an ___ man" needs an adjective starting with a vowel sound: eld- → elderly.
share → share. "offered to ___ a taxi": sh- → share. The infinitive after "to" takes the base form, not "shares".
traveling → traveling. "was ___ing" past continuous: trav- → traveling. This page uses American spelling with one l.
direction → direction. "in the same ___": dire- → direction. A common collocation — learn it as a chunk.
discovered → discovered. Past simple to match the story: disco- → discovered. "discover" (present) breaks the tense.
island → island. "the same small ___" + grown up on: isl- → island. Note the silent s.
visit → visit. "promised to ___ it": vi- → visit, base form after "to".

Score yourself one point per word, spelled exactly. 8 or more out of 9 on both: you are ready for harder texts — try the official free DET practice test.

Strategy: how to complete the words fast

Read the whole paragraph first. The complete first and last sentences tell you the topic and the tense.
Decide the word class before the word. After "the" or "their" → noun; after "to" → base verb; between "a" and a noun → adjective.
Do the easy words first, then come back to the hard ones — Duolingo gives the same tip.
Check the ending, not just the root. Plural -s, third-person -s, past -ed and -ing are where most points are lost.
Use the last 20 seconds to proofread spelling. A right word misspelled scores zero.
In one-word Fill in the Blanks, look for clue words with the same or opposite meaning, or a common phrase ("in the same ___").

Common traps

A real word that does not fit. "gro-" can start ground, grow, group or growth; only one fits the grammar.
Wrong tense in a story. Narratives are usually in the past; "disco-" must become discovered, not discover.
Agreement. "which co-" with a singular subject needs cools.
Silent and double letters. island, necessary, beginning, accommodate — keep a personal list of words you misspell.
Overthinking. In Fill in the Blanks you have 20 seconds; type the first word that fits grammar and meaning, check spelling, move on.

Also taking TOEFL? It has "Complete the Words" too

The 2026 TOEFL iBT Reading section includes a similar task called Complete the Words: a short academic paragraph where you finish partly written words. The same habits — word class first, check endings, proofread spelling — work on both. Practice the TOEFL version in our TOEFL reading practice.

Keep practicing the DET

Next: Listen and Type exercises — they test the same spelling accuracy by ear — and our DET speaking topics. Full test overview: Duolingo English Test guide.

Official free DET practice test

FAQ

What is fill in the blanks on the Duolingo English Test?

The DET has two "complete the words" question types. Fill in the Blanks shows one sentence with one unfinished word and gives you 20 seconds to type its ending (6–9 questions). Read and Complete shows a paragraph with several unfinished words and gives you 3 minutes (3–6 questions). Both count toward your Reading subscore.

Does spelling count in Duolingo fill in the blanks?

Yes. Duolingo's Question Guide says the spelling must be correct for a word to be marked right, in both Fill in the Blanks and Read and Complete.

Is each word scored separately in Read and Complete?

Yes. Every unfinished word in the paragraph is scored on its own, so one mistake does not cost you the whole paragraph.

Which sentences have no missing letters?

In Read and Complete, the title and the first and last sentences are complete, and the unfinished words are never next to each other. Missing words are never proper nouns or acronyms.

Is the TOEFL Complete the Words task the same?

It is similar: the 2026 TOEFL iBT Reading section includes Complete the Words, where you also finish partly written words in a paragraph. The skills transfer, but timing and scoring are different, so practice each test's own format.

Sources

DET Question Guide (2026), PDF — Fill in the Blanks and Read and Complete
DET help center: Test Structure
Duolingo English Test: free practice test (account required)