依据《劳动防护用品监督管理规定》，下列说法正确的是（） A．生产经营单位应当安排用于

单词拼写。

1. Asia is one of the seven c_____ in the world.

2. The famous actress was s_____ by a crowd, as soon as she got out of the car.

3. The _____ (风景) in the mountains is very beautiful.

4. Wealth is not always the _____ (标准) of success.

5. The field has an area of about four _____ (英亩).

脑的功能活动分属于五脏，与哪三脏关系更为密切

A．心肝脾

B．心肝肺

C．心脾肾

D．心肝肾

E．心脾肺

设二次型f(x₁，x₂，…，x_n)=x^TAx，其中A^T=A，x=(x₁，x₂，…，x_n)^T，则f为正定二次型的充分必要条件是
(A) f的负指数是0． (B) 存在正交矩阵Q，使Q^TAQ=E．
(C) f的秩为n． (D) 存在可逆矩阵C，使A=C^TC．

定量间伐方法