20. We usually _________________ (take) a bus to school, but this week we ___________ (go) by car. 21. This Tet, my family _______________(not buy) Chung cakes. We will make them. 22. Tet _______________(occur) in late January or early February. 23. Im really hungry. I ______________ (not have) lunch yet.

`20`. take `-` are going

`-` HTĐ, dấu hiệu: usually

`->` S + V(-s/es)

`-` HTTD, dấu hiệu: this week

`->` S + am/is/are + V-ing

`21`. won't buy

`-` TLĐ, dấu hiệu: this Tet

`->` S + won't + V-inf

`22`. occurs

`-` Chỉ một sự thật hiển nhiên `->` HTĐ

`->` S + V(-s/es)

`23`. haven't had

`-` HTHT, dấu hiệu: yet

`->` S + have/has + not + VpII