Last summer I took a course on _______ poisonous gases.

My bike is broken . May I borrow _______ ?

Did Alan see his old friends yesterday? —Yes, he did. Hehis old friends for several years.

Anhui is famous _____ Mount Huang.Many visitors all over the world come to visit it. [ ]

I will go to Beijing for a visit with my family during the winter holiday. —______.