John: Hello, Maria!（）.
Maria: Yes, I’m pretty busy lately. How about your studies

A．an old man
B．a stranger
C．a girl
D．not mentioned

A．Giving a tree a special shape and a definite height.
B．Removing small side branches and making a tree look less thick.
C．Allowing too many branches to grow in the middle.
D．Having a tree surrounded by many other trees.