Luke 12

Luke12:54 Then He also said to the multitudes, “Whenever you see a cloud rising out of the west, immediately you say, ‘A shower is coming’; and so it is.
Luke12:55 And when you see the south wind blow, you say, ‘There will be hot weather’; and there is.
Luke12:56 Hypocrites! You can discern the face of the sky and of the earth, but how is it you do not discern this time?

In geography we recently covered the topic "weather". And I can tell you: what Jesus says about the weather is correct! (I think even without geography lessons you can know, whether Jesus says the truth or not).
What I want to say, is that general knowledge is very important for evangelism. The more we know, the more we can talk to other people. Perhaps even some knowledge about the weather can help us to talk with others about God.
Here Jesus uses his backround knowledge to display their ignorance of this time. They can discern the face of the sky and of the earth, but they cannot discern this time. They can discern the geographic circumstances very well, but the time they cannot discern.
Perhaps the people understood Jesus' advice/warning because of his example.

What I just recently heard about was 為主耶穌讀書 (studying for Jesus). I don't want to focus on the exact meaning of this sentence (because actually you can think quite a lot about it).
However, I think that whatever we study, we can help God with our abilities. Even if we study chemistry or sociology (we might think, that studying them we cannot do anything for God) we can serve God with the skills we have (e.g. studying chemistry you can rebut or analyse the issue of the big bang or the origin of this world).