Leader of most countries in the world attended the UN meeting __________ in South Africa earlier thi

题目

Leader of most countries in the world attended the UN meeting __________ in South Africa earlier this year.
Held
To be held
会议一般不是to be held吗?为什么这里用不行?不是会议在前吗?
The chair looks rather hard ,but it is very comfortable to ________ .
Sit
Sit on
我一直搞不懂什么时候后面要跟介词.求详解

答案

Leader of most countries in the world attended the UN meeting 【（which was）held in South Africa earlier this year.】
【】是定语从句,修饰 the UN meeting,省略（which was）.To be held是将来时,前面用了attended了,是过去,所以不能用.
Sit on+ sth. 如果是sit,就是chair主动去坐.坐着舒服的是人,不是椅子.