16. on account of (=because of)由于，因为。
17. on no account(=in no case， for no reason)绝不要，无论如何不要(放句首时句子要倒装)
18. accuse…of…(=charge…with; blame sb. for sth. ; blame sth. on sb. ; complain about)指控，控告
19. be accustomed to (=be in the habit of， be used to)习惯于。
20. be acquainted with(=to have knowledge of)了解; (=to have met socially)熟悉
