You ________ go now. It ’s getting late.

Night ________ (fall), we hurried home.

he teacher told them since light ________ (travel) faster than sound,lightning ________ (appear) to go before thunder.

________ (fail) several times, they need some encouragement.

I found ________ to answer all the questions within the time given.

This diploma ( 毕业文凭 ) ________ that you have completed high school.

He asked me whether my brother ________ (fly) to Beijing.

Wood does not conduct electricity; ________.

The floor does not look so bad when ________ (sweep) clean. 

He fell asleep immediately last night; he must ________ (be) very tired.