Question

Stem-Changing Grammar Quiz

Answer 1

Stem changing verbs only change in some places 
yo, tu, ella/el/ud, and ellas/ellos/uds 
NEVER EVER in the nosotros or vosotros forms
So..
1.) is A
2.) is C
3.) is D
4.) is A
5.) is A
You have to think of the stem changers as " boot verbs" meaning on you conjugation chart  it goes down 3 and over 1 it looks just like a boot 
 
↓1↓      4
↓2 ↓     5   
↓3  ↓   → 6←

Answer 2

The answer is B for 1

2.)D

3.)C

4.)A

5.)D

Hope this helps!