一．单项选择
21.Leaves are found on all kinds of trees, but they differ greatly____size and shape.
A.on B.from C.in D.by
22.She is patient________her son and often explains everything he is curious about____patience.
A.with; in B.with; with C.in; with D...in; in
23.----Why does the lake smell terrible?
-----Because a quantity of water_______.
A.has polluted B.are being polluted
C.have been polluted D.has been polluted
24.The newly launched electronic newspaper has really______.
A.taken off B.got off C. turned off D.come off
25.I'll be late home because something has just_______at work.
A.come up with B.break out C.came up D.taken place
26.Her friend I referred to just now was_______for fraud.
