问题
选择题
We understand _______small changes to our land can have a big impact upon our environment __________ as we know is vulnerable enough.
A．what; which
B．what; where
C．how; where
D．how; which
答案
答案：A
考查固定句式以及定语从句。因为small changes是名词短语，所以用what引导。第二空是考查定语从句。As we know 是插入语，可以省略，which指代先行词environment在句中做主语。句意：我们理解，对土地的小小的改变可能会对很脆弱的环境有很大的影响。