Charles Darwin, a young man just out of university, knew perfect well that he had to depend on _____ when he set out on a voyage of discovery around the world. 

There is _______ in this book. So we should read it in the morning .

-How about his design?-Well, to tell the truth, it is______but satisfactory.

. I'd really appreciate ________ if you would turn off the lights before you leave.

---How many students have visited Yangzhou Museum?  ---____