请教几道简单的英语题!有几道题,知道答案不知道为什么选这个答案,请高人详细解释一下下?1.She was so angr

请教几道简单的英语题!
有几道题,知道答案不知道为什么选这个答案,请高人详细解释一下下?
1.She was so angry at all __A__he was doing _____she walked out without saying a word.
A. that, that B. which; that C. what; as D. that; which
2.Every minute must be made full use of ____B___our lessons, for the college entrance exam is coming.
A. going over B. to go over C. go over D. our going over
3.They are going downtown ____D____bus instead of _______their bikes.
A. by, by B. on; by C. by; in D. by; on
12.Where was it __B___the road accident happened yesterday?
A. when B. that C. which D. how