these are all correct.  But -abil may also stand for "manage to do something difficult".

Actually I send a longer post in another forum discussing the combined use of -ebil and -meli. 

thus for instance,

Çok sinirlense de susabildi. = S/he [managed to= was able to] keep his/her silence although s/he got very angry.

And for the negative:

Bütün baskýlara raðmen gitmeyebildi.= S/he managed to stay (not going) despite all the pressure. (not she might not go)

All sentences in that lesson are correct except for one

Ödemeksizin dükkandan çýktýlar. 



They left the shop without paying.

ödemeksizin dükkandan çýktýlar might be grammatically correct. However, noone would say it like that. here is the best translation for that sentence:

dükkandan para(sýný) vermeden çýktýlar

or

dükkandan ödemeden çýktýlar/ödemeden dükkandan ayrýldýlar.

TutorTurkish

Istanbul