硫色素荧光在碱性溶液中消失，在酸性溶液中又复出。（ ）
参考答案：错
Neither Jam nor his parents _______ places of interest here since they came to China.
A．will visit
B．has visited
C．have visited
D．visited
—What is the weather like this summer here?
—There ________ very little rain.
A．has
B．has been
C．are
D．have been
