Question

The book was written in 1946, _____ the education system has witnessed great changes.

A．when

B．during which

C．since when

D．since then

Answer 1

C

試題分析：
句意：這本書被寫于1946年，自從那時(shí)起，教育體制就發(fā)生了巨大的改變。when引導(dǎo)的定語從句，在從句中作時(shí)間狀語。后文用到完成時(shí)態(tài)，故用since when.
點(diǎn)評：本題極易選D. since then自從那時(shí)以來它不能引導(dǎo)定語從句，如果改為and since then即正確，本句since then只作時(shí)間狀語，沒有連詞功能。定語從句都不缺主，賓語時(shí)用關(guān)系副詞引導(dǎo)。