--You forgot your keys when you left home in the morning. --Good heavens,___________.
.How ___ I help them to understand when they won’t listen to me?
..In summer, food will go bad if________in room temperature.
..QQ, ______you can chat with your friends, makes communication easy.
.Mike must be angry with me, for he walked me without even saying hello.
._____ you don’t lose heart, I’m sure you can pass the coming examination.