The two old men ______ each other since 1970.

I doubt ________ the expensive medicine will work well.

How many more decades will have to pass____ scientists succeed in providing a cure for cancer

The girl ______ the toy carefully and was sure it was not the one she had lost.

ly, Chinese Premier Li Keqiang called on companies to give more opportunities to new graduates; _______, some privately run enterprises have announced increases in their hiring of new graduates.