So/ Because

I think she's very intelligent __________ she likes to learn new things and she understands them very quickly.

A lot of people like talking to my mom ______ she is very easygoing. She's funny, too!

My brother is lazy and untidy ___________ his room is always a mess.

When he's upset, he listens to music __________________ he can feel better.

My friend is unreliable. He's always late and he never calls ____________ I don't make plans to meet him anymore.

He doesn't do his homework __________________ he is lazy.

He studies a lot__________ he is the best student.

I passed my exam__________ I studied all weekend.

I could not talk to him ________ he was busy.

He was sick _______. they took him to hospital.