1 . 听下面一段独白，回答以下小题。
1. What will the temperature be at the bottom of the Grand Canyon four hours later?

A．26℃.

B．41℃.

C．43℃.

2. What is the most important thing to bring when hiking?

A．Some medicine.

B．Enough water.

C．Comfortable clothes.

3. What is the most common cause of death in the Grand Canyon?

A．Heat exhaustion.

B．Falling into it.

C．Getting bitten by snakes.

4. How many persons will go hiking together?

A．Three.

B．Four.

C．Five.