i want to know the reason to take that answer , why i choose that answer

ex) Airline passengers are requested to give their full attention until the flight attendants have emergency evacuation procedures.

A) demonstrated (O)

B) demonstration

C) demonstrating

D) demonstrates

the anser is A , its becuase when we use present perfect the verb should change into past participle form.

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Q:

1. The employees newly hired in the spring are outgoing and will probably have an easier time ______ to the costumer services position .

A) adjust

B) to adjust

C) adjusting (O)

D) adjustment

2. The planning officer can arrange the schedule ____ all employees to attend the regular research seminar .

A) as

B) in

C) for (O)

D) by

3. The engineer agreed that replacing the entire machinery would be ____ than trying to fix it .

A) cheep

B) cheaper (O)

C)cheapest

D) more cheaply

4. To get your device ____, you should contact us here at customer support .

A) to repair

B) repairing

C) repair

D) repaired

5. Ms, cooper has ____ requested permission to extend her leave of absence by another week in order to complete the research project .

A) formality

B) formal

C) formally (O)

D) formals

6. ____ chronically understaffed and underfunded , emergency medical teams are struggling to adequately provide emergency assistance to people .

A) Yet

B) Meanwhile

C) But

D) Although (O)

7. If delivery cannot be arranged immediately, we will inform you ____ the possible delivery date .

A) into

B) within

C) at

D) of (O)

8.LG Electronic Inc, ____ a wide features that allow users communicate with anyone anywhere in the world at any time by the end of the year .

A) will have offered (O)

B) has offer

C) had offered

D) offered

9. My first construction work ___without their support and assistance during the few months .

A) will be finished

B) wouldnt be finished

C) wouldnt have been finished (O)

D) will not have been finished

10. We could have reviewed the final report for the presentation if you ___ entered the data of the new device into my computer in time .

A) may have

B) could have

C) had (O)

D) were