根据句意，用括号内所给单词的适当形式填空。

1. I think _____(speak) English is more difficult than written English.

2. She is a quick _____(learn), and her English has got better day by day.

3. Be more careful! Don’t make any _____(mistake) in your writing.

4. I can't follow what you are saying. Could you please speak more _____

(slow).

5. The man laughed when he _____(realize) what had happened.

α-抗胰蛋白的主要功用是

A．运输铁
B．运输铜
C．能与细胞外血红蛋白结合
D．是丝氨酸蛋白酶的抑制剂
E．运输胆红素