After retiring, he was recommended to ____ gardening as a hobby．

 I ________ thank you too much for all your help to my son while we were away from home.

. I'd really appreciate ________ if you would turn off the lights before you leave.

 It never _____  humans until the mid­1990s that some animals can be cloned.

 If you _____ his wife’s income____ his own，the total of their income _____ 3000 yuan.

 Is it a wonder that ____little cells can store   　much energy?

As a senior high student, you should 　　your energy on how to master the skills of learning.

 — May I help you?

— Yes, I'd like to try on some sports jackets just like     I'm wearing. 

I wonder how it ____ that Chinese climbers successfully finished the torch relay on the Mount Qomolangma, where the air is so thin.

 ---Where did you save the drowning girl, ________ parents were both professors?

---It was from the lake ______ she often went fishing.