the back garden of our house has a lawn, _______ very pleasant to sit on in summer 这题怎么做？

the back garden of our house has a lawn, _______ very pleasant to sit on in summer 这题怎么做？

选第二个，which是指草坪，因为后面有sit on，己经有介词了就不能再用where了，所填的it是指不定式后的内容，作形式主语，保证没错

which is (非限制性定语从句）

我觉得应该是 it is

which is

这是一个连接词，连接LAWN 后面的一组词
1the back garden of our house has a __lawn__
2__lawn___ is very pleasant to sit on in summer

连接起来就要用WHIcH Is

答案是：A
【句意】我家的后花园有一片草坪，夏天坐在上面会令你心旷神怡。
因为which引出非限制性定语从句，在句中作主语，且和sit on 构成动宾关系。类似的句子有：This room is comfortable to live in 这句中live in 和this room构成动宾关系。故选A。