用动词的适当形式填空

1. I         (go) to the beach         (swim) with my friends yesterday.

2. Tom____(enjoy)____(work)with people.

3. The students of Class One     (wait)for their teacher now.

4. The little girl      (have)a lot of fun____ (learn) Chinese last year.

5. Kate is a reporter. She often____ (sleep) in the day and____(work) at night.

以下关于成体干细胞的描述正确的是（）

A.成体干细胞是一种多能干细胞

B.成体干细胞主要依赖不对称分裂方式来维持干细胞池的数量稳定

C.成体干细胞具有自我更新能力和多向分化潜能

D.神经干细胞是一种成体干细胞

E.成体干细胞增殖分化等能力虽不如胚胎干细胞，但它在临床上也具有广阔的应用前景