急性毒性试验时，每个剂量组小鼠不少于5只，大鼠3-4只。

问答题Which of the following teaching objectives does not refer to “language understanding”? （ ） A Understand that the 'ea' pattern has several sounds in English. B Know “be going to” could be used to describe actions, behaviors and events which are to happen in the future. C Tell the meaning of the following words: big, small, long, short, strong. D Understand people from different countries have different ways of greeting and show respect for each other’s custom.

问答题The fastest these animals can run is about 65kph and ____ their hunting methods have to be very efficient indeed.