People in many parts of the world are living longer lives now than people ____ in the past.
a) did
b) were
c) lived
d) had been
答案是a
想請教題目裡，than之前的部分，動詞是？ are living? lives?
承上題，如果動詞是 are living，did和were怎麼選？
謝謝

than people ( in many parts of the world ) lived inthe past . lived 和前面動詞一樣，所以用did 代替