单项选择题
The certificate for the refrigerating plant will（）soonI’d like to extend its validation now.
A.update B.finish C.outdated D.expire
单项选择题 （）, remedies must be taken to stop it as early as possible.
单项选择题 （）, the motion would continue indefinitely once it had started.
单项选择题 （） the bodies are, （） the friction will be.
