问题补充:
I know one of the things I was unsure about was hard it would be to climb this mountain.
A. what
B. that
C. however
D. how
答案:
A. what
B. that
C. however
(答案→)D. how
解析:考查感叹句:hard是形容词,用how修饰,what修饰名词,这句话是表语从句,如果不是感叹句应该是It would be hard to climb this mountain。对hard强调用how,句意:我知道我不能确定的一件事情是爬这座山会多难,选D。