Put the verb in brackets in the correct form 1. The Olympic games (be) .............. held once every four years. 2. People (start) ........................ to use computers about 50 years old.

1. The Olympic games are held once every four years.

-DHNB : once every four years 

2. People started to use computers about 50 years old.

-DHNB : about 50 years old.

FORM :

1,Thì hiện tại đơn :

S + V(s/es)

S + do/ does + not + V (inf)

Do/ Does + S + V  (inf)?

Note : Động từ tobe khi chia ở thì HTĐ chuyển thành am/are/is

1,C/T Quá khứ đơn 

(+) S + V2/ed +…

(-) S + did not + V (inf)

(?) Did + S + V (inf )?