I’m sorry to have ______ you with too many questions on such an occasion.

Try not to cough more than you can _______ since it may cause problems to your lungs. 

 The jewels that the rich lady was wearing that evening must be ______.

I first met Lily five years ago. She ___ as a nurse in a hospital at the time. 

Having lived in China for 8 years, Helen has a good ____________ of both English and Chinese.