Scientists were flying over a desert, or hilly wasteland, or a mountain region in order to search for （） in the ground.

单项选择题According to the passage, in looking for a job, the students（）

A．must make an arrangement for an interview
B．may follow their interests and ambition
C．will surely get a chance to improve their positions
D．will always visit every employer"s office

单项选择题According to the passage, only （） trees can give us shade, beauty, and products.

A．beautiful
B．healthy
C．old
D．young