To be on the safe side, we should fill up the tank now, because we ______ run out of gas on the way.
It is uncertain ______ side effects these weight-loss drugs will bring about, although hundreds of thousands of patients have taken it.
– Which color do you prefer, red or black? -- Red. For red _____ a sense of energy and strength.
According to our principal, all children should be encouraged to realize their full _______.
The black box is a necessary device on an airplane, which records its speed, direction and whether everything on the airplane______ normally.
Stella was disappointed to find her new plan ______and fell into great depression.