压强的度量标准有()种。
A.1
B.2
C.3
D.4
参考答案:B
Parents often ask their children _____ their Internet friends because they may be in danger.
A.to meet
B.to not meet
C.meeting
D.not to meet
饲料生产企业召回的产品,应当在企业质量机构负责人的监督下予以无害化处理或者销毁。