根据下面对话内容及所给的首字母提示，在对话后的横线上写出对话中所缺的单词。单词必须写完整。

Zhou Lan (Z) and Bruce (B) are talking about learning English.

B: What do you find hardest in learning English?

Z: I find listening really hard. Sometimes it" s difficult to u     1     : It" s not easy to catch its meaning.

B: Well, you need 1    2    of practice. The more you listen, the e    3    it becomes. .

Z: But I don' t find the best w     4    to do that. Would you please lend me a h     5   ?

B: W     6    not get a radio? It's helpful to listen to English p     7    on the radio.

Z: It s     8    like a good idea.

B: Practise m     9    , and you'll find l   10    is not so hard.

Z: I'll try my best to do that. Thank you.

1.                 2.                 3.                4.              5.                 

6.                 7.                8.                9.                10.             

腐蚀品按其酸碱性大小可分为（）类。

A、一

B、二

C、三

D、四