Although very hard, he didn’t pass the exam.
China is developing fast.That’s________I think those of my colleagues who deal with China affairs should visit China.
Our bad living habits will destroy the earth.Only by changing________we live can we save the earth.
It was only when I reread his poems recently________I began to appreciate their beauty.
I got an email from my old friend last Sunday.Until then,we________in touch for nearly 3 years.
Many people believe that hunger is only a problem in the developing countries.________,it is a problem all over the world.