oxford_guide_to_english_grammar

13 THE PASSIVE PAGE 142
When the main clause and the infinitive or gerund clause have the same subject,
then we do not repeat the subject.
I expect to be invited to the wedding.
(= I expect that I shall be invited to the wedding.)
The understood subject of to be invited is I.
113 Active forms with a passive meaning
1 Gerund
The active gerund after need, want (= need), require and deserve has a passive
meaning.
These windows need painting. The cupboard wants tidying out.
We cannot use the passive gerund here.
2 To-infinitive
a
We sometimes use an active to-infinitive to talk about jobs we have to do.
We've got these windows to paint.
I had some homework to do.
When the subject of the sentence is the agent, the person who has to do the job,
then we use the active infinitive, not the passive.
If the subject of the sentence is not the agent, then we use the passive infinitive.
These windows have to be painted.
The homework was to be done by the next day.
After the subject there, we can use either an active or a passive infinitive.
There are a lot of windows to paint/to be painted.
There was some homework to do/to be done.
NOTE
We do not normally use the passive infinitive for leisure activities.
There are lots of exciting things to do here.
b
After an adjective phrase, the infinitive is usually active.
This machine isn't safe to use.
The piano is too heavy to move.
That box isn't strong enough to sit on.
If we use a phrase with by and the agent, then the infinitive is passive.
The piano is too heavy to be moved by one person.
(= The piano is too heavy for one person to move.)
NOTE
Compare ready and due.
The meal was ready to serve/to be served at eight.
The meal was due to be served at eight.
3 Main verbs
There are a few verbs that we can use in the active form with a passive meaning.
The singer's latest record is selling like hot cakes.
This sentence doesn't read quite right.
This sweater has washed OK.