在生产过程中，煤矿井下作业场所空气中一氧化碳的来源有煤自燃（）
A.人员呼吸
B.煤岩层涌出
C.放炮
参考答案：C
选出能够替换句中划线部分的选项。
a. trouble b. quite worried c. very important d. running after e. waste things
( ) 1. The dog likes chasing the chick.
( ) 2. It’s crucial that we study English well.
( ) 3. She’s anxious because of the test.
( ) 4. Xiao Ning found garbage in front of the house.
( ) 5. Don’t bother your father. He is busy with his work now.
“西三角经济圈”地区城市中，1998-2008年比全国农村居民人均生活消费支出增速快的有（）
A．0个
B．1个
C．2个
D．3个
