*Cấu trúc chung: THÌ HIỆN TẠI ĐƠN:

$-$ Với động từ to be:

$(+)$ S + am (I) $/$ is (He, She, It, Danh từ số ít) $/$ are (You, We, They, Danh từ số nhiều) + $...$

$(-)$ S + am (I) $/$ is (He, She, It, Danh từ số ít) $/$ are (You, We, They, Danh từ số nhiều) + not + $...$

$(?)$ Am (I) $/$ Is (He, She, It, Danh từ số ít) $/$ Are (You, We, They, Danh từ số nhiều) + $S$ + $?$

$-$ Với động từ thường:

$(+)$ $S$ $+$ $V$ $(s/es).$

   + I, You, We, They, Danh từ số nhiều: giữ nguyên động từ.

   + He, She, It, Danh từ số ít: Thêm "s" hoặc "es" sau động từ.

$(-)$ S + do/ does + not + V (Bare).

$(?)$ Do/ Does + S + V (Bare)?

$------------$

$1.$ The major cause of water pollution in Vietnam is the weakness in industrial wastewater management.

$2.$ Many factories use freshwater to carry away waste the plants like canals, rivers, and lakes.

$3.$ Most of them do not have a wastewater treatment system.

$4.$ Industrial wastewater is directly discharged like canals, lakes, ponds, rivers causing serious pollution to surface water.

$5.$ For example, in $2008$, Vedan factory, a sodium glutamate plant, released their untreated industrial wastewater to ThiVai River caused tons of fish and ducks in the river to die.

- Thì quá khứ đơn: S + V (-ed/ bất quy tắc).

$6.$ Another cause of water pollution in Vietnam is the lack of awareness among citizens.

$7.$ Every day people generate a lot of garbage, then they throw it directly into canals, rivers, and ponds.

$8.$ They collect water from these sources to do the laundry, wash dishes, and bathe, then they throw the dirty water that contains a detergent to shampoo directly into them.