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．differB．shrinkC．failD．decline
Smiles around the world _____ be false, _______ other feelings like anger, fear or worry.
A．must; hideB．shall; hiding
C. may; hideD．can; hiding
The doctor tried to laugh my brother _____ his fears about the coming operation.
A. from B. against C. off D. Into
---Why are you so crazy about music?
--- Because I can always find in music _____ peace that is missing in _____ world full of challenges.
A. the; a B. the;/ C. /; a D. /; the
