Sometimes we have specific problems with our mother; sometimes, life with her can just be hard work. If there are difficulties in your (1) , it’s best to deal with them, (2) remember that any (3) should be done (4) person or by letter. The telephone is not a good (5) because it is too easy (6) either side to (7) the conversation.
Explain to her (8) you find difficult in your relationship and then (9) some new arrangements that you think would establish a (10) balance between you. Sometimes we hold (11) from establishing such boundaries because we are afraid that doing (12) implies we are (13) her. We need to remember that being (14) from our mother does not (15) mean that we no longer love her. If the conflict is (16) and you cannot find a way to (17) it, you might decide to give up your relationship with your mother for a while. Some of my patients had (18) "trial separations". The (19) allowed things to simmer down, enabling (20) .
（12）（）
A.it
B.which
C.what
D.so
参考答案：D
解析：
[考点解析] 选项D“SO”与其前面的“doing”结合在一起构成“doing so”(这样做)这一动名词短语形式在“that”引导的宾语从句中作主语。“doing so”(这样做)指代的是其前面的“establishing such boundaries”(确定这样的界线)。考生在解题时要注意句子中各语言成分这间的指代关系。
