So suddenly ________that the animals in the zoo looked very frightened during the total solar eclipse (日全食)．
A．did the sky turn dark B．the sky did turn dark
C．turned the sky dark D．was the sky turned dark
—Have you finished your book report?
—Not yet. I couldn't________on it with so loud music next door last night.
A．draw B．devote C．direct D．concentrate
Once we have________some knowledge, things do not become more difficult, but comprehensible.
A．required B．acquired C．inquired D．inspired
The chief editor demanded that the article ________immediately.
A．must be submitted B．would be submitted C．submits D．be submitted
Tom is a promising student. I am sure that with his________effort, he will make a very successful scientist.
A．usual B．constant C．content D．normal
We are hoping that these measures taken by the local government will help________things a bit.
A．sweep up B．speed up C．make up D．save up
