Question

The boy over there is the only one of the students who ________ to Europe．

1. A.
   has been
2. B.
   have been
3. C.
   has gone
4. D.
   have gone

Answer 1

A
思路解析：over there说明the boy就在眼前，因此排除C、D两项；先行词是the only one of the students，是一个人，因此答案是A项。
绿色通道：要熟记各种学过的词汇、句型。可以简单地记为：“one of the+可数名词复数”作先行词时，定语从句谓语动词用复数；“the only one of +可数名词复数”作先行词时，定语从句谓语动词用单数。