A:一只蝗虫
B:全部蝗虫
C:全部昆虫
D:全部生物
读“西气东输线路图”, 完成小题:
根据对话内容及问题选择正确答案( )
— Sorry, I didn't pass the exam, and then what should I do?
—I think perhaps you should be careful next time.
若单项式2x2ym与-13xny3的和仍为单项式,则m+n的值是____
下列运输任务与适宜的运输方式搭配正确的是