Though it's cloudy now, it ______ get sunny later.[ ]
A. can
B. may
C. must
D. need
答案:B
They find themselves surrounded by colorful rocks, fishes, seashells and plants, all ____ slowly in the blue water.
A.waving and moving
B.waved and moved
C.waved and moving
D.waving and moved
简述器官发生的过程。