How can I change these sentences to the passive voice? 1- I went to Alex. (change it to passive) 2- He looked at me. (change it to passive)
A sentence is in the passive voice when the object of the action in the sentence is used as the subject (grammatically speaking). So the person or thing doing the action is not actually the subject of the sentence.
Here are the most likely ways that you could put your example sentences into the passive voice.
Sentence 1. Alex was gone to by me.
Sentence 2. I was looked at by him.
In both cases, the object of the actions (Alex in sentence 1, you in sentence 2) are actually the grammatical subject of the sentence.
A sentence in the active voice will have a transitive verb, that is, the action from the subject will be transferred to the object.
1. Strictly speaking the sentence should read: 'I went to meet Alex at some place.' In such a sentence the verb is used intransitively. However, in the sentence 'I went to Alex' which in all probability is a colloquialism the action of 'going' is transferred from the subject 'me' to the object 'Alex.'
So the sentence in the passive voice will read as 'Alex was gone to by me.' But since the sentence in the passive voice sounds awkward and inelegant it will never be used to convey the meaning which the speaker wants to convey, that is, 'he went to meet Alex [at some place]'
2. The action of 'looking' is transferred from the subject 'he' to the object 'me.'
So the sentence in the passive voice will read as 'I was looked at by him.'