---You look very healthy. ________do you exercise? -----I exercise three times a week. 

Mike was ill yesterday,        he didn' t go to school.

 —Happy Teachers’ Day! Here are some flowers for you. —      beautiful flowers they are! Thank you!

—— Hurry up. The bus is coming! —— Oh, no, we mustn’t cross the street ______ the traffic lights are green.

The room was dark, _______ I turned on the lights.