保护视力要养成良好的用眼习惯,连续看书写字多长时间休息片刻或向远处眺望()
A、集中精力学习,不必休息
B、1小时左右
C、2小时左右
D、3小时左右
参考答案:B
—I have tried very hard to find a solution to the problem, but in vain.
—Why not consult with Frank? You see, ________.[ ]
A. great minds think alike
B. two heads are better than one
C. a bird in the hand is worth two in the bush
D. it's better to think twice before doing something
试述破伤风的治疗原则。