1. —How big are the manatees?
    —They're about on      __    (foot) long and 1, 000 pounds heavy.
2. It was       __   (discover) that pandas were endangered.
3.  —What are they doing?
     —"They are trying _______ (help) the environment.
4.  We should take our own bags when _______(shop).
5.  I was _______ (surprise) to see Jim at the party.  I thought he was in hospital.
6.  Visiting zoos are like to read _______ (live) textbooks for young people.
7.  Do you know what place is _______ (suit) for tigers to live in?
8.  The environment _______ (pollute) is more and more serious.
9.  My elder brother decided to go abroad to continue his _______ (educate).
10.  The Students' Union urges all the students       __     (stop) chewing gum.

A. How old are you
B. How tall are you
C. How big are you
D. How are you