题文
【2012山东德州】I enjoy fresh air so I always sleep with the window open _____ it is really cold.
| A.unless | B.when | C.if | D.since |
【2012山东德州】I enjoy fresh air so I always sleep with the window open _____ it is really cold.
| A.unless | B.when | C.if | D.since |
试题篮
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