I’m a bit of a sucker for Venn diagrams. When I was recently asked by a student about the Chinese modal verbs 会, 能, and 可以 (all of which can be translated into English as “can”), I recalled a nice Venn diagram on the topic and dug it up.
What creates the most confusion with these three modal verbs is not that they can all be translated into “can” in English. The problem is that they are usually explained over-simplistically something like this:
会: know how to
能: be able to
可以: have permission to
This is not a bad start, but this sort of definition is eventually revealed as insufficient to the learner because in usage, the three modal verbs actually overlap. Enter the Venn diagram. The image below is a reconstruction of the one on page 95 of Tian Shou-he’s A Guide to Proper Usage of Spoken Chinese:
A = ability in the sense of “know how to” (“会” is more common than “能“)
B = permission/request (use “能” or “可以“)
C = possibility (use “能” or “可以“)
D = permission not granted (use “不可以“)
E = impossibility (use “不能“)
Yeah, grammar needs more Venn diagrams.
Update: I’ve been informed that this diagram is actually a Euler Diagram. Oops. I stand corrected. I should have read up on the requirements for Venn Diagrams first! (Hey, some of those extensions are pretty cool!)