3. Read and write.
Yesterday we had a school trip to the zoo. The zoo manager told us a lot about the zoo. In 1999, there were only two tigers at the zoo, but there are six tigers now. There was only one elephant twenty years ago. Now, ten elephants live happily here. There were fifteen monkeys then, but now there are fifty. There were forty cats at the zoo in 1999, but there are no cats any more. Now people like to keep cats at home.

| |In 1999|Now|
|----|----|----|
||1) |2) |
||3) |4) |
||5) |6) |
||7) |8) |

1) two tigers 2) six tigers 3) one elephant 4) ten elephants 5) fifteen monkeys 6) fifty monkeys 7) forty cats 8) no cats

根据短文内容，1999年老虎数量为two tigers，现在为six tigers；1999年大象数量为one elephant，现在为ten elephants；1999年猴子数量为fifteen monkeys，现在为fifty monkeys；1999年猫数量为forty cats，现在为no cats。