单项选择题
A.不填;a B.不填;the C.the;a D.the;the
A.positive(肯定的) B.negative(否定的) C.neutral(中立的) D.nervous(紧张的)
A.they have a lot of free time B.they can go to hospital if they are injured C.their life is short of excitement D.they no longer need to hunt for food