如图，下列叙述正确的是（　　）

A．由图分析可知f₁是营养物质，进入静脉血

B．图中f₈进入B时，膈肌处于舒张状态

C．图中D为皮肤组织，则2可能为汗液

D．图中表示排泄途径的是1，2，3

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) .

（15）（）

A.instantly

B.reluctantly

C.necessarily

D.steadily