题干
Everyone in our class was working hard and doing what we could _______ a good college.
A：enter
B：to enter
C：entering
D：entered
答案(点此获取答案解析）
B
A：enter
B：to enter
C：entering
D：entered
,学名肉桂酸，又名β-苯丙烯酸，主要用于香精香料、食品添加剂、医药工业、美容、农药、有机合成等方面，其合成路线(部分反应条件略去)如下所示:
