She didn’t mention her troubles to Mr. Li，who might have helped her ______.

I don’t like her face;        , she smokes, which is something I hate.

My uncle lost his ID card yesterday. ______, a boy found it and gave it back to him last night. 

 ________ the machine begins to work, you can’t stop it _____.

As is known to all language learners, the newly learnt words will soon be forgotten unless ______ used in everyday communication.