回复：回复：小测验：我下面这个帖子有三处不地道的地方（不是时态），大家来找，我晚上公布答案？

However, your grammatical mistake of using "many" in front of an uncountable noun, your wrong use of "promise to somebody" and your mistake in "I should have had spent " were not pointed out.

The sentence above is not good either. The however doesn't sound to follow the logic flow and if it does, it is not used in the right place.  The rest is confusing.  "and your mistake",better have a "," in front of and.

 

...class is becoming too much (of) a distraction for me