1 going

`to` có was (động từ tobe ) nên là thì QKTD `to` dùng going

2 going/prepare 

`to` before +Noun/clause nên dùng Ving thay cho Noun

`to`should+(not)+V0

3 ride/fall

`to`should+(not)+V0

`to` may+V0

4 doing

`to`busy+Ving

5 have ever seen

`to` có ever nên dùng thì HTHT

`-` form : S+have/has+(not)+V3/ed......

6 will / do

`to` vì if+HTĐ nên nó là if 1

7 sat

`to` có last year nên dùng thì QKĐ

8 to meet

`to` enough to do sth : đủ để làm gì

9 haven't rained

`to` có for+time nên dùng thì HTHT

`-` form : S+have/has+(not)+V3/ed......

10 is falling

`to` có look out chỉ vc đó đang xảy ra tức thì nên dùng thì HTTD

1. They asked him if he was ready ( go )..to go....on holiday ( ready + to V1)

2. Before ( go )...going....on holiday, you should ( prepare )..prepare...everything (before + Ving, should + V1)

3. You should not ( ride ) ..ride....your bike too fast. You may ( fall )..fall.. off it (may +V1)

4. From 8am to 9pm tomorrow i'll be busy ( do ) ...doing.... Judo  (busy + Ving)

5. This is the tallest tower i ..have.. ever ( see )..seen..  (ever là dấu hiệu thì hiện tại hoàn thành)

6. What..will..you ( do ) if someone throws an egg at you ?    ( if là dấu hiệu tương lai đơn)

7. We ( sit )...sat...on the beach last Sunday when we saw a shark   ( last là dấu hiệu quá khứ đơn)

8. You were not early enough ( meet ) ...to meet... her  (enough + to V1)

9. It usually rains much at this time of a year but this year it ( not/rain )....hasn't rained....for six months   ( for là dấu hiệu hiện tại hoàn thành)

10. Look out ! the tree ( fall )...is going to fall.... soon