一般性的草坪草的高度在（）cm时就必须进行修剪了，一年最少应修剪4～5次。A.6～1

阅读短文，判断句子是“√”否“×”正确。

     Look, this is my family photograph. The old man is my grandfather. He is shorter than his son, my father.

The woman is my mother. I'm her daughter. The boy is my cousin. I am younger than him. His mother is

Aunt Baiyun. Uncle Zhaowei is Aunt Baiyun's husband. We're a happy family.

( ) 1. My grandfather is shorter than my father.

( ) 2. My cousin is a girl.

( ) 3. My cousin's father is Uncle Zhaowei.

( ) 4. Aunt Baiyun and Uncle Zhaowei have a daughter.

女性，35岁，既往有胃溃疡病史，5小时前突发上腹部剧烈疼痛，伴恶心、呕吐，呕吐物为胃内容物，考虑为胃溃疡穿孔引起的急性腹膜炎。现患者出现面色苍白、四肢发凉，测血压70/40mmHg，表现为休克症状。该患者发生休克的主要原因为（）

A.剧烈疼痛

B.腹膜吸收大量毒素，血容量减少

C.肠内积液刺激

D.大量呕吐致液体丢失

E.腹胀引起呼吸困难

对谐波电流来说，（）谐波电流分量会在中性线上叠加。

A.3次

B.5次

C.7次

D.9次

下列各结构面中，属于次生结构面的是( )。

A．沉积间断面
B．劈理
C．板理
D．风化裂隙

浸出法取油工艺按操作方式可分为（）和（）等。