1．They didn’t finish the project on time; I regretted(后悔) that I didn’t give them a hand.
2．Billy has been praised for his ability to observe people and events around him and make fair comments(评论)．
3．It is well known that giving up smoking can reduce(减少) the risk of heart disease.
4．At the end of the news, they often give you a summary(总结) of the main stories.
5．We made some interesting discoveries(发现) about our own family.
6．China exported(出口) this special strain of super hybrid rice to many other countries last year.
7．Health and environmental problems have increasingly become the focus(焦点) of attention.
