大全 sec19-21，求助~

sallyruru

1.After gradual declension down to about 39 hours in 1970, the workweek in the United States has steadily increased to the point that the average worker now puts in an estimated 164 extra hours of paid labor a year.

(A) After gradual declension down

(B) Following a gradual declension down

(C) After gradual declining down

(D) After gradually declining
(E) Following gradually declining
答案说following一般作介词，这里应用连词after, 后面用动名词，故D is correct.
没理解，弱弱的问一句啥时候要用介词，啥时候用连词啊？

sallyruru

哦，懂了~膜拜，谢谢~