`9.` There are 2 rulers in my bag. 

⇒ S + have/has + N `=` There is/are + N + in/on/at + S 

`10.` I go to school on foot. 

⇒ walk `=` go on foot 

`11.` My house is in front of the tree. 

⇒ S1 + tobe + behind + S2 `=` S2 + tobe + in front of + S1 

`12.` Lan go to work at five forty-five. 

⇒ five forty-five `=` a quarter to six 

`13.` My room has a board. 

⇒ S + have/has + N `=` There is/are + N + in/on/at + S 

`14.` Mr Quang goes to work by his car. 

⇒ drive the car to work `=` go to work by car 

`15.` My sister goes to school at a quarter past seven. 

⇒ at seven fifteen `=` at a quarter past seven.

`16.` The house is in front of the mountain. 

⇒ S1 + tobe + behind + S2 `=` S2 + tobe + in front of + S1