ごごに vs. ごごは and ばんに vs. ばんには?


I wrote the following sentences (in an exercise in which I had to tell how I
spent the day):

> ごごに、にほんごをべんきょうしました。  
>  ばんに、ばけもののこをみました。

A Japanese person corrected them like this:

> ごごは、にほんごのべんきょうをしました。  
>  ばんには、ばけもののこをみました。

As I was speaking about me in the previous sentences, I thought the subject
(me) was implied. I don't understand why the subject here is the afternoon
itself or the night?




I think your sentences are natural.

And you omitted the subject 私は in these sentences.

ごごに and ばんに mean "in the afternoon" and "in the evening / at night",
respectively.

I think は and には can be used in your sentences instead of に.

The difference between に and は and には is written in this link. [When do you
use は/に for どようびは/に?](https://japanese.stackexchange.com/questions/8269/when-
do-you-use-%E3%81%AF-%E3%81%AB-
for-%E3%81%A9%E3%82%88%E3%81%86%E3%81%B3%E3%81%AF-%E3%81%AB)




I think your sentences are natural.

And you omitted the subject 私は in these sentences.

ごごに and ばんに mean "in the afternoon" and "in the evening / at night",
respectively.

I think は and には can be used in your sentences instead of に.

The difference between に and は and には is written in this link. [When do you
use は/に for どようびは/に?](https://japanese.stackexchange.com/questions/8269/when-
do-you-use-%E3%81%AF-%E3%81%AB-
for-%E3%81%A9%E3%82%88%E3%81%86%E3%81%B3%E3%81%AF-%E3%81%AB)

