在NBDP遇险通信中，“SILENCEMAYDAY”表示（）使用的信号.A.对干扰电

阅读理解

      Every country has its own way of cooking. American people have their way of cooking, don't they?

      Most people in the United States like fast food, but if you think that American people don't like

cooking, you are wrong. It's true that most Americans eat fast food for their breakfast and lunch, but they

also think cooking is interesting. Parents see the importance of teaching their children how to cook, and

most Americans say that home cooked meals are the best.

      Americans have their own way of cooking. For example, baking  (烘烤) is the most popular way of

cooking in America. Most American families have ovens. American cooks pay attention to (注意) the

balance of food. In planning a big meal, they try to cook meat, a few vegetables, some bread and often

some sweet food. They also like to make the meal look beautiful. There are many kinds of food of different colors, so the meal is healthy and looks beautiful, too.

根据短文内容，选择最佳答案。

1. Most Americans       .

A. don't like cooking                    

B. cook food in the morning

C. eat fast food                          

D. like having a picnic

2. Most Americans       . 

A. don't eat fast food for their breakfast or lunch

B. have fast food for their breakfast or lunch

C. like to eat fast food for supper

D. don't have breakfast or lunch

3.         is the most popular way of cooking in the USA.

A. Baking            

B. Cutting        

C. Frying      

D. Boiling

4. How does an American cook balance different kinds of food?   

A. He cooks a lot of meat.

B. He cooks meat, vegetables, bread and sweet food for a big meal. 

C. He makes the food delicious.   

D. He cooks a lot of vegetable. 

5. Which is right according to the passage? 

A. The meal looks beautiful because the food is in different colors. 

B. American people do not like to cook food at home.          

C. American parents do not like to teach their children to cook.    

D. Most people in the United States don't like fast food at all.  

在高空匀加速水平飞行的飞机上自由释放一物，若空气阻力不计，地面上的人看物体的运动轨迹是（　　）

A．倾斜的直线

B．竖直的直线

C．不规则曲线

D．抛物线

雷公藤最常见的不良反应是（）

A.骨髓抑制

B.肝功能异常

C.胃肠道不良反应

D.神经系统损害

E.性腺抑制

如图（甲）所示，一个弹簧一端固定在传感器上，传感器与计算机相连. 当对弹簧施加变化的作用力（拉力或压力），在计算机上得到了弹簧长度的形变量与弹簧产生的弹力大小的关系图象，如图（乙）所示. 则下列判断错误的是

A．弹簧产生的弹力和弹簧的长度成正比；

B．弹簧长度的增加量与对应的弹力增加量成正比；

C．该弹簧的劲度系数是200N/m；

D．该弹簧受到反向压力时，劲度系数不变

植物体的结构层次中不含有（）

A、细胞

B、组织

C、器官

D、系统