根据下面所设情景，选择恰当的选项。
1. 当你想问别人邮局在哪里时，应说：[ ]
A. What is the post office?
B. Is this a post office?
C. Do you know where the post office is?
2. 当你想问那张贺卡多少钱时，应说：[ ]
A. How much is the card?
B. How is the card?
C. How old is the card?
3. 当你想问对方是否会照相时，应说：[ ]
A. May I take your picture?
B. Can you take a picture?
C. Can you help me to take a picture?
4. 当你想问发生了什么事时，应说：[ ]
A. What happening?
B. What is happen?
C. What happened?
5. 当你想问火车站是否有许多人时，应说： [ ]
A. How many people are there in the train station?
B. Are there many people in the train station?
C. Does the train station have many people?
