The train he was looking forward to ______ only a few minutes ago. A arrives B arrived C arriving D had arrived
________ where we can stay for a week.
Carbon dioxide(CO2)_______ from burning fuels is the most common of the so-called greenhouse gases.
We must apply what we have learned to our daily work because in no case_____ from practice.
Mrs. White found her husband surrounded by letters and papers and_______ very worried.
----What are you busy with? ---- The conference_______ in our city next week.