Nelson Mandela devoted all his life to the struggle of the African people and of every nation that seeks freedom．
| A．it | B．one | C．those | D．that |
We shall not start the project until it __________ by the committee.
| A．will be approved | B．approves |
| C．has been approved | D．is to approve |
Bears ______ fat stores throughout the summer and fall to have energy enough to last them through their winter sleep.
| A．pack up | B．build up | C．bring up | D．take up |
With many cities in China dreadfully blanketed by thick haze, the environmental problem is _____ Chinese people concern most nowadays.
| A．what | B．which | C．where | D．when |
According to scientists, our mental abilities begin to _____ from the age of 27 after reaching the highest level at 22.
| A．differ | B．shrink | C．fail | D．decline |
Smiles around the world _____ be false, _______ other feelings like anger, fear or worry.
| A．must; hide | B．shall; hiding |
| C．may; hide | D．can; hiding |