-Do you know our hometown at all?-No, this is the first time I _______ here.
With many cities in China dreadfully blanketed by thick haze, the environmental problem is _____ Chinese people concern most nowadays.
According to scientists, our mental abilities begin to _____ from the age of 27 after reaching the highest level at 22.
Smiles around the world _____ be false, _______ other feelings like anger, fear or worry.
The doctor tried to laugh my brother _____ his fears about the coming operation.
---Why are you so crazy about music?--- Because I can always find in music _____ peace that is missing in _____ world full of challenges.