please check some sentences

[Anonymous]

i've been thinking that they understand in class.
autually, they seems make a mistake of the test.

so, i'm worry about this midtermtest.

[izabela]

Hi,

I am not sure what exactly you want to say, but here is the correction according to my understanding of your sentences.

I thought that they understood in class. However, they made errors on the test, so I am worried about this mid-term test.

Iza

i've been thinking that they understand in class.
autually, they seems make a mistake of the test.

so, i'm worry about this midtermtest.

[Tdol]

In British English, we make mistakes 'in tests'.