1. It cannot be denied that superstitious ...exist in many cultures ( believe). 3. Very young children shouldn't eat sugary food.  Sugary food.... em cần giải thích cụ thể ạ

1. beliefs - superstitious beliefs: mê tín dị đoan - belief phải thêm s vì động từ exist đằng sau nguyên mẫu

3. Sugary food shouldn't be eaten by very young children.

* - Active voice: $S_{1}$  + should (not) + Vo + $S_{2}$ 

  - Passive voice: $S_{2}$ + should (not) + be + $V_{3/ed}$  (+ by $S_{1}$)