简述在一般货物贸易中，生产型外贸企业办理出口收汇核销和出口退税时分别需提供的凭证。

Passage 2:Hong Kong has about 40 public beaches. Some of the beaches are among the best in the world. People can go there for a swim. You can go to most of them by bus. To go to some of the beaches you must take a boat. There are clothes changing rooms and places to buy food and drink on most of the beaches.You will swim there without danger if you remember these instructions: 1) Never swim alone.2) Never swim after a meal or when you feel hungry or tired.3) Don’t stay in the water too long.4) Never go out in a boat if you can not swim.Remember: A red flag means that it is dangerous for anyone to go into the water. A blue flag means that it is dangerous for children.

We can reach ________ by bus.

A．all the public beaches

B．any public beach

C．only a few public beaches

D．most of the beaches