Question

【题目】The twin sisters have learned a lot_____ they came to China．

A. when B. as soon as C. since D. after

Answer 1

【答案】C

【解析】句意：这对孪生姐妹到中国以来学了很多东西。A. when当……时候；B.as soon as一……就……；C. since自……以来；D.after:在……之后。根据语境，本句指的是过去某一动作对现在造成的影响或结果。“since+一般过去时句子”表示从过去某段时间以来，故答案选C。