Answer:
Change the 'and' to 'but.'
Change 'a test' to 'any tests'
Explanation:
<u>You wrote:</u> My best subject is Spanish, and I haven't passed a test this month.
<u>After Changing:</u>
My best subject is Spanish, but I haven't passed any tests this month.
If you change it, it sounds more like you are unhappy about your Spanish skills and makes more sense.
Answer:
The mantle is approximatly 2,900 km thick and it can get to be extreemly hot!
Explanation: