A certain amount of flexibility is built into the system.
A certain amount of stress is vital to provide motivation.
A certain amount of our sleep is a time filler in the winter.
A certain amount of dreaming is good, like a narcotic in discreet doses.
A certain amount of water is added, and the rice simmers until most of the water evaporates.
A certain amount of stress is vital to provide motivation and challenge, and to give significance to an idle life.
Stress is not all bad news. A certain amount of pressure enables you to work better, and studies show that it can strengthen your immune system.
A certain amount of bonus will be given to the family with only child. Necessary assistance will be granted to the parents with only child when they retire in line with local conditions. ]]
A certain amount of care or pain or trouble is necessary for every man at all times .A ship without a ballast is unstable and will not go straight.一定的憂愁、痛苦或煩惱，對每個人都是時時必需的。一艘船如果沒有壓艙物，便不會穩定，不能朝着目的地一直前進。
