英文兩樣唔明 幫幫手

首先，副詞 (adverb) 不一定要放在句中或者在 have 和 been 之類的詞中間。依照不同種類和情況，句首、句中和句尾都可以放副詞。
放在句首的例子: Then, I go to school.
放在句中的例子: I always play.
放在句尾的例子: I come home late.

有時候副詞放不同位置亦不會影響文義，如上面第一句可以寫成
I then go home.
亦有時候副詞位置是不可改變的，如上面第三句就不可以寫成
I late come home.

根據 Michael Swan 的《英語用法指南》(Practical English Usage)，表示次數的副詞，包括 always, ever, usually, normally, often, frequently, sometimes, occasionally, rarely, seldom 和 never 等，一般情況下都放於句中助動詞 (will, have, can, do, etc.) 或 is, am, are, was, were 之後、其他動詞之前。
例1: I have never seen a dinosaur.
例2: I am seldom late for work.
例3: I usually go hiking with my father.

而如果句中有兩個助動詞，這類副詞一般會放在兩者之間。
例: She must always have been wanted to join us.
但亦有例外。
例: I could have completely finished my work today.

書中亦提到，usually, normally, often, frequently, sometimes, occasionally 等亦可用於句首或句尾 (而不影響文義)。
例1: Occasionally I think I'm too mean.
例2: I go to the park sometimes.

而 always, ever, rarely, seldom, never 等則一般不能用於句首或句尾。
例外是 always 和 never 可用於祈使句 (imperatives) 句首。
例1: Always stop and look before cross the road.
例2: Never do this at home!


回應你的問題，諸如 Yes, I do sometimes / usually / often. 等句子都是正確的，但 No, I do never. 或 Yes, I do always. 等則不合使用慣例。

從以上眾多的例子和例外你就會知道，英文的副詞位置其實沒有必然規律可尋。

其實你的理念都啱嘅。

但“no,i do never”就不可以,因為NEVER是“負面”答案。

正確是I do not……就要寫成I never do…

而間題Do you…………?正面答案是 I do………所以啱。

(因為單是睇subject同verb,之前你的答案就變成正面了)



希望幫到你

In my point of view, the sentence "Yes, I do sometimes." is WRONG. Grammar and usage is wrong.

As you suggest, "Yes, I sometimes do." is RIGHT.