raig loves his students, he is very strict withthem in their performances

There is a small object ________ a pin on the desk.[ ]

How did you find your visit to Lijiang River? — To tell the truth, it’s hard to _______ a more fascinating place.

The book, ____ are true stories about great scientists of the 20th century, is well worth reading.

You have a sweet tooth. It may be hard for you to lose weight.— ______, but I just can’t help it.