571.Though he is in his late sixties,the well-known biologist begins each day _________ a sense of adventure and a sense of curiosity.
A.in
B.with
C.of
D.at
572.It was clear that the small grocery was _________ people he owed money to.
A.at the expense of
B.at the risk of
C.in the way of
D.at the mercy of
571.答案是B;
begin with 以…开始。
572.答案是D;
at the expense of 以…为代价;at the risk of 冒着…的危险;at the mercy of 任凭…的摆布,听任。