短文改错。

    Jim Green teaches our ____ English. He has been in China for more than two year____. He has been to many interesting places in Beijing, and____  he has not yet been to many others ____ parts of China. Last week he goes ____ to Mount Emei in Sichuan Province with his family. Many people like travel ____ by air, but Jim ____ family think that traveling by train is the best. It is much cheap ____ and far more enjoyable than a rushing trip by air. He ____ had a wonderful train ride to Chengdu after ____ they went to Mount Emei by bus.

翡翠是人们喜爱的一种装饰品，翡翠的主要成分是硬玉，其化学式为NaAl(SiO₃)₂。其中Si的化合价是(   )

从所给出的单词中选出合适的完成对话。

 on     Wednesday   with   piano   busy

Mike: Are you free ____ Monday afternoon, Bill?

Bill: No, I am not. I play basketball on Monday afternoon.

Mike: How about Tuesday afternoon?

Bill: I am sorry. I play the ____ on Tuesday afternoon.

Mike: How about ____ afternoon?

Bill: No, I am not. I go to the museum ____ my brother.

Mike: You are very____.

Bill: Yes, I am busy from Monday to Wednesday.

动物的种类多种多样，下列关于动物的特征与分类叙述正确的是（    ）