4 . 用方框中所给单词的适当形式填空。每词限用一次。

if; make; sound; patient; stranger

1. It’s important for us not to trust the ________ on the Internet.
2. Alice ________ many new friends since she returned to LA last year.
3. It ________ great! They are planting a lot of trees on the sandy hills.
4. Leo is ________ in teaching his grandma how to use the computer by herself.
5. After class, my teacher asked me ________ I understood what we learned.