单项选择题A.She can hear them crying very loudly at the zoo.B.She’s heard them panting and was told it was laughter.C.She’s read about it from Darwin.D.She used to work at a zoo.
单项选择题A.He saw the big tower he visited on TV.B.He has visited the TV tower twice.C.He has visited the TV tower once.D.He will visit the TV tower in June.