18.　 You should keep the fish tank clean. 你应该保持鱼缸干净。

17.　 Fantail goldfish are different from other goldfish.==Fantail goldfish are not the same as other goldfish. 扇尾金鱼与其它金鱼不一样。

16.　 You ought to put some stones at the bottom of the fish tank. 你应该在鱼缸底部放些石头。

15.　 Make sure the water is not too cold or too hot. 确保水不太烫也步太冷。

14.　 Fantail goldfish are easy to look after.== It’s easy to take care of fantail goldfish.

扇尾金鱼容易照顾。/ 照看扇尾金鱼是容易的。

13.　 I can’t study because she makes too much noise. 　我不能学习因为他制造太多的噪音。

12.　 It is a good idea to clean its hutch every day. 每天清扫它的兔笼是个好主意。

11.　 It is very important not to give them too much food.. 不要给它们太多的食物是很重要的(事)。

10.　 It’s necessary to walk them in the park once a day if you want them to be healthy.

如果你想要他们健康的话，你有必要每天带他们到公园里散一次步。

9.　　　 You oughtn’t to feed your dog at your table. 你不应该在桌子边喂狗。