1．It is the custom of this academy to make an annual (每年的) award for outstanding researchers in chemistry.
2．In face of failure, it is most important to keep up a good state (状态) of mind.
3．There has been below average rainfall (降雨量) this month.
4．An apple falls down because of gravity (重力)．
5．The sky was full of dark masses (堆，块) of clouds.
6．To live a long and healthy life, we must learn to have a balanced (balance) diet.
7．He has thought of a good idea for the promotion (promote) of his products.
8．Water was found at a depth (deep) of 30 metres.
9．The commercial (commerce) bank is willing to lend money to these customers.
10．They are working under extreme (extremely) pressure at the moment.
