清朝前期，只允许广州一地进行对外贸易，且仅由十三行负责。清朝统治者之所以这样做，

物体带电的三种方式______、______、感应起电．

教育学萌芽阶段有哪些基本特点？

Which one of the following statements about the t - distribution is TRUE（）

A. The t- distribution is the appropriate distribution to use when constructing confidence intervals based on large samples.

B. Compared to the normal distribution, the t -distribution is more peaked with more area under the tails.

C. The t - distribution approaches the standard normal distribution as the number of degrees of freedom becomes large.

符合甲状腺功能亢进症代谢率增高的表现是（）。

A.神经过敏、失眠

B.心动过速、收缩压增高

C.肠蠕动增快、腹泻

D.甲状腺弥漫性肿大

E.怕热、多汗、食欲亢进

分析《凤凰涅槃》的浪漫主义特色。