侏儒症是由下列哪项因素引起的[ ]
A．幼年期缺乏甲状腺激素
B．幼年期缺乏生长激素
C．成年期缺乏甲状腺激素
D．成年期缺乏生长激素
答案：B
—I feel stressed in my study from time to time. I don't know what to do.
—_________.[ ]
A. You should keep relaxed.
B. What about keeping your worries to yourself?
C. Why not ask the youth workers for advice?
D. You'd better pay no attention to your study.
现行棉花国家标准规定，五级锯齿白棉，长度29毫米，马克隆值为C级，其质量标识为（）。
