用所给单词的正确形式填空

小题1:A number of ________(student) often help the old people on weekends.

小题2:Thanks a lot for ________ (teach) us so well, Miss White.

小题3:Tom is much ________(thin) than his friends.

小题4:He is not funny, and he is always very ________(serious).

小题5:He would like ________ (have) a cup of tea.

再生障碍性贫血时（）

A．全血细胞减少

B．红细胞及血小板正常

C．红细胞及血红蛋白均减少

D．血小板减少伴形态异常

E．周围血存在大量原始和幼稚白细胞