1,with:固定搭配discuss (sth.) with sb.
2,B :find it ...
3,People had taken many years to build the Great Wall.
4,the改为a :没有the large number of这一说法
5,of doing:the way of +名词或动名词
6,B :主语是number,系动词则为修饰单数的is或was,但是今年学生人数已定,所以要用过去式was
7,though:表示虽然
8,D:stop sb.from doing sth.固定搭配
9,What a
10,look at