Here are the sentences with the verbs in the correct form:
Alex needed to borrow some money, so he decided to ask Henry.
Fred's grandpa wasn’t able to look after himself anymore, so Fred started to look after him.
If Sarah doesn’t remind Pam to phone her brother, she’ll forget about it again.
The joke was really funny. I couldn’t help laughing at it.
Ted wanted to apply for a part-time job, but Ann persuaded him not to do it.
Are there any disadvantages of riding a bike to work?
My favourite baseball team lost the game despite playing well.
Everybody was sure it was a difficult problem to solve.
Having an electric kettle enables you to boil water quicker.
Did you get into trouble for being late?