Well, I am confused about the directions I should give to the test section with the following characteristics:
There are ten situations that can be represented by proverbs on the question-sheet. The students are to write the proverbs. One situation needs one proverb only. Which instruction is the best:
This is one way:
Write a separate proverb for each situation.
Alternatively, something like this might work:
Write proverbs unique to each situation.
You could write something twice as long that would make the meaning even more explicit—but you need to accept a reasonable trade-off between simplicity and deliberate misunderstanding. In other words, there's always some way of forcing an incorrect meaning onto something—but it become impractical to guard against it beyond a certain point. (It would take convoluted reasoning to be able to make the above two sentences mean something different than what you're looking for.)
I would try to be clear in what you are asking for, so I would use the slightly wordier:
For each of these situations, write a proverb that represents that situation.
It's a bit longer but I feel it is clearer that the proverbs whould be specific to one situation, and each situation should have one proverb.
Both Rob Lamden's and Jason Bassford's suggestions are good. Nevertheless, I think they can be improved.
Neither suggestion appears to recognize that the choice of proverb is restricted to those supplied. Now I concede that the restriction may be implied, but my experience is that trusting people to recognize the implicit is foolish, to say the least. So my suggestion is:
Select, from the ten proverbs provided, the one most appropriate to each described situation without selecting one more than once.
In other words, you are asking for a one-to-one correspondance and expecting the application of understanding and judgment to making the correspondences.
