不注意。 doesn't pay a lot attention(eg: The thief stole my money when I 不注意) 别注意。no need to pay attention in sth(别注意 quite strange for me,we seldom use that) 不能这样。(you)Can't do that. 别这样。Don't do that. 迟到了。(I am )late 没迟到。(I am )not late 别迟到。Don't be late