Scientists Move Toward a New Way to Keep Official Time

Study the questions and tasks

Work through the material below, or start the interactive practice above to complete an attempt. Try the exercises before opening any answer or transcript sections, then use them to review your work.

Practice level

B2. Try this level if you can follow the instructions and understand most of the language; choose an earlier level if you need more support.

Question formats

Fill in the blank (dropdown)

How to approach this practice

Read the complete sentence and notice the subject, verb form, time reference and word order before answering.

1. Question 1 · Fill in the blank (dropdown)

   Choose the correct option for each blank.

   Scientists ___ the system used to connect official time with Earth's rotation.

   Choices for blank 1

   1. have voted to change
   2. has voted to change
   3. have vote to change
   4. have voting to change
   Check answers and explanations

   Blank 1

   have voted to change

   The present perfect shows a recent decision with current relevance.

2. Question 2 · Fill in the blank (dropdown)

   Choose the correct option for each blank.

   The planet's spin ___ by a very small amount.

   Choices for blank 1

   1. has slowed down
   2. have slowed down
   3. has slow down
   4. has slowing down
   Check answers and explanations

   Blank 1

   has slowed down

   The present perfect correctly describes a past change affecting the present.

3. Question 3 · Fill in the blank (dropdown)

   Choose the correct option for each blank.

   A leap second is an extra second ___ to official time when necessary.

   Choices for blank 1

   1. added
   2. add
   3. adding
   4. to adding
   Check answers and explanations

   Blank 1

   added

   The passive participle is required after “is” in this definition.

4. Question 4 · Fill in the blank (dropdown)

   Choose the correct option for each blank.

   The conference, ___ recently met in Versailles, decided to abandon the system.

   Choices for blank 1

   1. which
   2. who
   3. where
   4. what
   Check answers and explanations

   Blank 1

   which

   A non-defining relative clause needs “which” for the conference.

5. Question 5 · Fill in the blank (dropdown)

   Choose the correct option for each blank.

   If the two watches ___ apart, one must be corrected.

   Choices for blank 1

   1. gradually move
   2. gradually moved
   3. will gradually move
   4. gradually moving
   Check answers and explanations

   Blank 1

   gradually move

   The first conditional uses present simple after “if.”

6. Question 6 · Fill in the blank (dropdown)

   Choose the correct option for each blank.

   A longer adjustment period could ___ those systems easier to manage.

   Choices for blank 1

   1. make
   2. makes
   3. making
   4. to making
   Check answers and explanations

   Blank 1

   make

   After “could,” the base verb “make” is grammatically required.

7. Question 7 · Fill in the blank (dropdown)

   Choose the correct option for each blank.

   Scientists continue ___ measurement standards to the natural world.

   Choices for blank 1

   1. to adapt
   2. adapted
   3. adapting to adapt
   4. to adapting
   Check answers and explanations

   Blank 1

   to adapt

   The verb “continue” can be followed by a to-infinitive here.

What to review next

After checking an answer, explain the rule in your own words and write a new sentence using the same pattern. Revisit any rules you could not explain.

A focused practice result shows how you did on these tasks. Use several activities across skills to decide what to study next; one practice score does not certify an overall CEFR level.