When you read the book, you’d better make a mark ____ you have any questions.
If a substance has a higher density, ____ 2, 000kg/ m³, it will not float on water.
Had it not been for the fact that she_____ in the leg, she might have passed the exam.
---What do you think of Jack?---He is not a bad boy. ______, he’s a pretty good one.
_____ a mobile phone can you ring____ you want to talk with anywhere.
---Was it midnight_____ the heartbreaking news came_____ he passed away?---I am afraid so.