____you stepped into the lab with your shoes on? You are supposed to take them off before you enter it.
It was not what he said but the way he said it ______ made a great difference to me at last..
—Why is it ________ so many people enjoy eating on the run? —Of course, the most obvious answer is that fast food is fast.
— Why did the dinner party start so late last night? — It was _____ that caused him to serve dinner an hour later than usual.
---I can’t find Mr. Brown. Where did you meet him this morning? ---It was in the hotel _______he stayed. A thatB which C where D when
Was it in 1969 _____ the American astronaut succeeded_____ landing on the moon?