英文文法問題

1.
a. It's sometimes hard to see and sometimes not.
(Merriam-Webster's Dictionary)
b. Costumes change, but sometimes not the spirit.(http://www.jsonline.com/story/index.aspx?id=524589)
c. Why does a fart sometimes smell and sometimes not?
(http://answers.google.com/answers/threadview?id=392844)

2. Always響以前小學老師會教你地要用simple present tense．如
She always spells my name wrong.
其實不盡然，在某些情況下，如這事件是會不斷重覆發生的，可用present continuous tense. 如：
1. The teacher is always telling us to study English more.
2. Mary is always arriving late for work.

1.sometimes...
e.g. i don't sometimes eat sushi.
2.其實always前面唔係一定要+is/am/are/was/were.....前面99%都唔會有is/am......
e.g. i always go to (某地方)...
咁樣咪唔洗囉..
希望你岩洗啦..