Whether it will do us harm remains_______ .
It is in the hall behind the teaching building _____ we usually have our PE lessons on rainy days.
We _____ on this project for four hours. Let’s have a rest.
There are over 58,000 rocky objects in _____ space, about 900 of which could fall down onto _____ earth.
—Did you catch what I said?—Sorry. I _____ a text message just now.
I feel so excited! At this time tomorrow morning I _____ to Shanghai.