S=people

O=this mountain

V=climbed

This mountain has been climbed by no one before

S : You

O : this bill 

V : (don't have to) pay

This bill doesn't have to be paid until next week

ok

This bill doesn't have to be paid until next week.

giúp mình với :

Find S-O-V and write passive :

You don't have to pay this bill until next week

You: S

pay: V

this bill: O

-> This bill doesn't have to be paid until next week.

This bill doesn't have to be paid until next week

S : Who

O : this letter

V : wrote

By whom was this letter written?

By whom was this letter written?

S: I 

V: have finished

O: the work

The work has been finished (by me) 

S : I

O : the work

V : have finished

The work has been finished 

S: I

O: the work

V: have finished

The work has been finished 

S: I

O: the work 

V: have finished

=> The work has been finished by me

giúp mình với : Write passive and find S-O-V :

They (S) had finished (V) preparations (O) by this time the guests arrived

=> preparations had been finished by this time the guests arrived

giúp mình với :

Find S-O-V and write passive :

Is she killing her dogs ?

She: S

kill: V

her dogs: O

-> Are her dogs being killed by her?

Are her dogs being killed by her?