高等植物细胞和动物细胞之间，在细胞分裂的机制上的不同点是（）。
A.着丝点分裂
B.细胞质分裂
C.纺锤丝的功能
D.中心粒存在
参考答案：B, D
But for the sudden rainstorm, our trip to Hong Kong _____ a very pleasant one. [ ]
A. was
B. had been
C. would be
D. would have been
