以下哪项不是牙髓的特点（）

A.被坚硬的牙本质壁包围

B.基质富含纤维且具有黏性

C.有丰富的侧支循环

D.牙髓是一种疏松的结缔组织

E.牙髓对刺激只表现为痛觉

用所给单词的适当形式填空。

1. It's too late. Let's________ (take) a bus to school.

2. Who________ (want) to go there now?

3. They are________ (laugh) loudly.

4. He says nothing and goes ________ (quiet).

5. Oh, my dear! Please________ (do) drive so quickly.