(in) last spring

[sitifan]

Welcome to my house (English Dialogue) - Educational video for Kids
https://www.youtube.com/watch?v=O07X1XLK4tM&list=PLUxvTjyCKXuNsESLZrCpVxKIwJ6o64Gze&index=2
0:29 My family planted them in last spring?
https://books.google.com.tw/books?i...egQIBBAC#v=onepage&q="in last spring"&f=false
“Several who came in last spring went out again in the fall, satisfied in their own minds that this is no country for them, and we are of the same opinion,” wrote Gordon Bettles the better part of a century ago.

In the above sentences, is the preposition "in" redundant, optional or obligatory?

 

[Raymott]

I'd use "during". The preposition there is not mandatory, but "in" sounds wrong.

 

[sitifan]

- They last visited Paris last spring.
=> The last time .....................................
a- The last time they visited Paris was last spring.
b- The last time they visited Paris was in last spring.
https://www.usingenglish.com/forum/threads/249642-Last-spring-or-in-last-spring
Only A is correct.

 

[Raymott]

That's right.
And c- "The last time they were in Paris was during last spring" is also correct.

 

[GoesStation]

Number one was written by a non-native speaker. "In" is incorrect there.

Number two doesn't say "in last spring", which is incorrect. Parse it like this: "Several who came in last spring went out again in the fall …." Does that help?