The education of ______ young is always ______ hot and serious topic.
Each member country WTO must ___________ its laws and regulations and compete on the principle of fairness and cooperation.
Mary ______ all the housework, she dropped herself into the sofa, sighing with relief.
Scientists say human activity contributes to climate change, but they do not agree on the rate_______ climate change may be developing.
Everybody has ______ responsibility to save water, if future generations are to enjoy _____similar standard of living to the one we enjoy now.
______ the new life in Qingdao, the old man lived happily with his son after leaving his home in the countryside.