[ Modals ]
So far scientist have not ___ to successfully devise a mechanism
A. been able
B. need
C. must
Select your answer:

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Homonyms › ViewHer novels regularly ___ the depths of human despair.
a. plum
b. plumb
PRESENT SIMPLE - CHILDREN › View
Choose the correct verb: “Today, my English lesson “….” at 6.30 in the afternoon.”
A. to start
B. star
C. starts
D. start
