493.With the effects of global warming, trees______ their leaves much later in the year.
A.are losing
B.have lost
C.lost
D.were losing
494.John seems happy，even though his wife left him and he lost his job.
I think he _______ to put on a brave face.
A.will try
B.has tried
C.tries
D.is trying
493.答案是A;此句说明现在的情况。
494.答案是D;考查动词的时态。根据上文语境的暗示，此处应指现阶段的情况，故选D。
