consist in

consist in, consist of

都是consist+介词搭配的词组。
consist in: 表示“在于...”之意；说明一样事物的性质，这种性质大都是抽象的、非物质的。

• happiness consists in trying to do one's duty，not in amassing wealth.
  快乐的源泉在于尽义务，而不在于积聚财富。
• the best remedy for tuberculosis consists in rest.
  肺结核病的最好良药就是休息。
• the value of this teaching method consists in the interest it stimulates in the students.
  这种教学法的优点是在于能引起学生的兴趣。

consist of: 表示“包含”，“由...组成”之意。说明组成某一事物的部分，这些部分大都是具体的、物质的。

• water consists of oxygen and hydrogen.
  水由氧和氢组成。
• this delegation consists of ten famous actors.
  这个代表团由十名著名影星组成。
• our golf club consists of 150 members.
  我们的高尔夫俱乐部有一百五十名会员。

1. Tact consists in knowing how far we may go too far.
   机智在于知道自己可以过分到什么程度。
2. The beauty of the plan consists in its simplicity.
   该计划的妙处在于简洁明了。
3. Consider the postage stamp: its usefulness consist in the ability to stick to one thing till it get there.
   想想那邮票吧：其用处在于它能粘住一样东西直至达到目的为止。