1, We have donated books for street children for 2 years.
⇒ For + khoảng thời gian ⇒ dùng thì ht hoàn thành
2, Did they visit their grandparents last Sunday?
⇒ Last Sunday ⇒ dùng thì qk đơn
3, Children enjoy watching cartoon because it is funny.
⇒ Enjoy + V(ing): thích thú làm j
4, I haven't seen him since last month.
⇒ Since + mốc thời gian ⇒ dùng thì ht hoàn thành
--- XIN TRẢ LỜI HAY NHẤT NHA ^^ ---