细菌、真菌在生态系统中的作用是 [ ]
A．消费者食物的来源
B．把有机物分解为无机物
C．使无机物变成有机物
D．维持生态系统的平衡
答案：B
用括号里的词的适当形式填空。
1. I have lost the address. What______ I _______(do) ?
2. Could you please______ (not laugh) at others?
3. After an hour, they _______ ( finish)their homework and ______(go) shopping.
4. The parents are always________ (complain)about their children's rudeness(无礼、粗鲁).
5. They don't know why you talked to them so _______(angry) .
