一个数，如果除了1和它本身还有别的因数，这样的数叫做合数；由此一个合数至少有3个约数．
答：一个合数至少有3个约数．
故选C．
阅读理解
Come and see the Indian elephants and the new tigers from America. The bears are waiting to meet
you, and the monkeys from China are waiting to throw (扔) things at you. The lovely koalas from Australia are waiting to laugh at you, and the giraffes from Zambia are waiting to look down on you.
1. How many kinds of animals are talked about in the passage?
A. Four.
B. Five.
C. Six.
D. Seven.
2. Now Mr Smith is in the zoo with his two sons, one aged 14 and the other 10. How much are the
tickets together? _____.
A. $4. 00
B. $2. 00
C. $3. 00
D. $1. 00
3. People can visit the zoo at .
A. 9 :30 a. m. Monday
B. 3 :30 p. m. Tuesday
C. 3 :30 p. m. Saturday
D. 8 :30 a. m. Sunday
4. From the passage we can guess the animal "giraffe" must be very .
A. fat
B. long
C. tall
D. strong
5. Which of the following can we do in the zoo? _____.
A. To take a few nice photos
B. To give some food to the koalas
C. To touch the monkeys on the head
D. To throw things everywhere
以下对残根的处理正确的是（）
A.所有残根都需拔除
B.所有残根都应保留
C.只要没有临床症状，残根可不进行根管治疗
D.对于缺损至眼下的残根，可在完善的根管治疗后用正畸的方法牵引至合适位置
E.以上均正确
