matching verb tenses

[nick52]

hi !
I saw him waiting for a train to arrive !!
Is this sentence correct or it should be arrived as it was from the past tense, i think the verb tenses is not matching over here, can u please explain to me !! Another similar sentence is I forgot to take photo. why there is take instead of took

[charliedeut]

Hi !
I saw him waiting for a train to arrive[no space]!! One exclamation mark is enough.
Is this sentence correct [Yes, it is] or should it should be "arrived" as it was from the past tense? I think the verb tenses is are not matching over here, can u you please explain to me !!? Another similar sentence is "I forgot to take a photo". Why there is it "take" instead of "took"?

Hi and welcome

See corrections above.

charliedeut

[5jj]

Only the first verb in any series of verbs is tensed:

I see him waiting......I saw him waiting......I have seen him waiting......I had seen him waiting......
I forget to take ... .....I am forgetting to take .... .....I forgot to take ........ I had forgotten to take ... .....I

[Tdol]

Another similar sentence is I forgot to take photo. why there is take instead of took

We don't use to took.