问两道情态动词的题1 Since she is angry,we________A had better to leav

问两道情态动词的题
1 Since she is angry,we________
A had better to leave her alone B should leave her alone C might as well leave her alone
D must leave her alone
问下A为什么不对
2 She quickened her pace in order that she________with the others.
A may catch up B might catch up C could have caught up D might have caught up
问下C 为什么不对