唔該幫我睇下呢句有無錯gammar~~~

1. 要明 not only 同埋 but also 既用法就得.
not only 同 but also 係要玩平衡, 既係not only 後面既句子結構同but also 後面既要一樣.
以你既句子做例子,
We not only have to absorb sufficient nutrition, but also do more exercise a day.

not only 後面跟verb, 所以but also後面都跟verb.
不過, 它地仲有另一個用法. 就係inversion ( 倒裝句 )
Not only do we have to absorb sufficient nutrition, but we also have to do more exercise a day.
因為not only 放向subject 前, 所以跟住果句要好似d question 咁加個do
當然, 如果個subject 係he/she/it, 就加does
當然, 你都可以隨住個meaning而選擇用can/will/should...etc
總之好似問題咁就得ga la, 好易記ga
但係最煩既係but also 果句要加返個subject 向but 同also之間

不過, 有d 情況下個but可以唔寫, 又有d情況下個also 可以唔寫, 但係唔可以兩個都唔寫. 不過, 為左減少錯處, 所以我一向咪都寫哂. ^^ 同埋唔想記咁多野.

2. 個the 係多餘既, sufficient 己經係adj, 後面無必要加of.
a day = every day, 而every day 本身己經係adv, 所以前面係永遠無prep.
順帶一提, every week, every month, every year 前面都無prep.

We not only have to absorb the sufficient of nutrition, but also do more exercise within a day.
唔係甘通lor~~
Correction
We do not only have to take the sufficient amount of nutrition, but also have to do more exercise within a day.

For your reference!!

Not only that we need to have sufficient amount of nutrition, we ought to do enough physical exercise a day.


You sentence's suggestions:
1) not to say "the sufficient of nutrition" ===> simply say " sufficient nutrition" is OK.
2) may be adding "need" is better AND delete "within" is better ==> but also need to do more exercise a day.