So far scientist have not ___ to successfully devise a ...

[ Modals ]

So far scientist have not ___ to successfully devise a mechanism

A. been able

B. need

C. must

Select your answer:
A B C D E

Other quiz:

Grammar › View

He _ _ _ _ not drive a car.

A. Does

B. Do

C. Is

D. Are

First Conditional Sentence › View

If my friends ________, I will be very happy.

A. comes

B. come

C. came

D. have came

Grammar › View

What is the correct abbreviation for October?
A. Octo.
B. Oct.
C. Oct
D. Octob.

Indefinite Pronouns › View

______ bought me a drink yesterday.

A. Something

B. Everybody

C. Someone

D. Somewhere