Probably the most detailed resource you're going to find online (or anywhere, for that matter!) for this is the
Collins COBUILD Grammar Patterns 1: Verbs:
http://www.corpus.bham.ac.uk/publications/index.shtml
>
https://arts-ccr-002.bham.ac.uk/ccr/patgram/
Unfortunately in the online freebie "reprint" they haven't provided the indexes from the book, making it less easy to find (think of) more beyond the Ch 1 sec 4
V pron-refl string, so I'll type up the Pattern Finder index's relevant entries for you.
They are:
Verb patterns
V pron-refl 62-68
V pron-refl about n/-ing/wh 341
V pron-refl adj 282
V pron-refl after n 448
V pron-refl against n 344, 345
V pron-refl among pl-n 362
V pron-refl amount about n 342
V pron-refl as n/-ing 351
V pron-refl as to wh/n 356
V pron-refl at n 359
V pron-refl between pl-n 362
V pron-refl -ed 308, 309
V pron-refl for n 369, 370, 371
V pron-refl for n/-ing 370
V pron-refl from n 376-379
V pron-refl inf 298
V pron-refl -ing 288, 290
V pron-refl in n 383, 384, 386
V pron-refl into -ing 397
V pron-refl into n 390, 394
V pron-refl n 274, 275, 276, 277
V pron-refl of n 400
V pron-refl on n 405-410
V pron-refl out of n 415
V pron-refl prep 321
V pron-refl prep/adv 313-324
V pron-refl that 300
V pron-refl to amount 426
V pron-refl to-inf 291-296
V pron-refl to n 420, 422, 427-432
V pron-refl to n/-ing 425
V pron-refl with n 438, 441-447
V pron-refl with quote 303
Phrasal verb patterns
V P pron-refl 62-68
V pron-refl P as n/-ing 351
V pron-refl P from n 376, 377
V pron-refl P into n 394
V pron-refl P prep/adv 316, 323
V pron-refl P to n 429, 430, 432
V pron-refl P with n/-ing 443
Here also are the more student-friendly breakdowns and exercises from the accompanying
Collins COBUILD Verbs: Patterns and Practice book:
http://img16.imageshack.us/img16/7720/ccvpp14.jpg
http://img299.imageshack.us/img299/9955/ccvpp15.jpg
But doubtless you could find at least some sort of detail in more widely-available grammar exercise books like Murphy (or indeed the
Collins COBUILD Student's Grammar, though even this may, like the grammar pattern stuff, be out of print and therefore harder to get nowadays).
By the way, I could if you like also post the info and lists from the relevant entries of the original COBUILD
English Grammar (which I have on CD-ROM).
Regarding the translation of 'relax' in Chinese, I wasn't aware that it necessarily involved the Chinese equivalents of reflexives, but I suppose that your student's English usage could certainly be due to certain aspects of Chinese usage generally (that, or studying incorrect English materials previously). There's no chance they mean 'relax BY myself', is there?
Anyway, stuff like COBUILD should help make the facts clear (to you the teacher at least - might need to boil things down a bit for the students though, doo luck with that!), so there hopefully shouldn't be any need to talk too generally, decontextually or "theoretically" about the "how" and "when".