1. Learning a foreign language is not easy, and it comes to speaking, it can be more difficult.
A. when B. unless C. once D. while
【答案】A
【解析】
【詳解】考查從屬連詞和固定句型。句意:學(xué)習(xí)一門外語(yǔ)并不容易,當(dāng)談到口語(yǔ)時(shí),可能會(huì)更困難.A.when當(dāng)…時(shí)候;B.unless除非;C.once一旦;D.while當(dāng)…時(shí)候,雖然。根據(jù)句意可知,這里使用固定搭配when it comes to “當(dāng)說(shuō)到……的時(shí)候”。故選A。