27. She locked her room _____ a thief would break into it.
One of the greatest benefits of stamp-collecting is that they are based on common interests,________ appearance,age or wealth.
It is ________ he often fails in exams ________ makes his parents worried about him.
— Do you think that housing price will keep ________ in the years to come?— Sorry,I have no idea.
After two months’ training,the astronauts are ________to adapt to the conditions of weightlessness.
I smell something ________ in the kitchen.Can I call you back in a minute?