对气体加热其温度一定升高。

A. It is sad that you can find comfort with friends only in Facebook.
B. It is convenient to chat with others across communities with Facebook.
C. It is terrible to reveal personal feelings in Facebook.
D. It is satisfying to find the social norm changing over time with Facebook.

A. Personal information.
B. Political scandals.
C. Business affairs,
D. Religious events.

A. Major European airlines will go bankrupt,
B. Europeans will pay much less for traveling.
C. Traveling time by train between major European cities will be cut by half.
D. Trains will become the safest and most efficient means of travel in Europe.