As the sea ice melts sooner each swimmer,polar bears are forced to come ashore e
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As the sea ice melts sooner each swimmer,polar bears are forced to come ashore earlier and face food shortages _____ they have stored enough fat to last them through the season.
A.before
B.unless
C.since
D.until
试题答案
A
本题考查连词。句意：因为海冰融化得比游泳者早，北极熊没来得及为整季储存足够的脂肪，就被迫提前上岸，面临食物短缺。before conj.在……之前；比……早些。