“端午节：赛龙舟，包粽子”的习俗文化属于 A．汉族 B．壮族 C．傣族 D．蒙古

阅读短文，判断正(T)误(F)。

     It was Sunday yesterday. The weather was fine. Jim and Tom went to the zoo by bike. They saw lots

of animals there. They were very happy.  At eleven o'clock, they were hungry and thirsty. So they bought

some hot dogs and some milk. They had them for lunch. Then they played in the zoo. They jumped and

ran. They had a good time.

( ) 1. The weather was fine yesterday.

( ) 2. They went to the park by bike.

( ) 3. They saw lots of animals.

( ) 4. They had some bread and milk for lunch.

( ) 5. They had a good time.

关于力和运动，下列说法中正确的是（　　）

A．物体在恒力作用下可能做曲线运动

B．物体在变力作用下不可能做直线运动

C．物体在恒力作用下不可能做曲线运动

D．物体在变力作用下不可能保持速率不变

如图甲所示，小芳在做“探究影响滑动摩擦力大小因素”的实验时，操作的错误是              ．纠正错误后，应拉动弹簧测力计使木块作       运动．若在木块上再放一个砝码，则木块运动时受到的滑动摩擦力将       （选填“变大”、“变小”或“不变”）．

(2)若将木块沿竖直方向截去一半后，测得木块所受的滑动摩擦力变为原来一半．他由此得出：滑动摩擦力的大小随接触面积的减小而减小．你认为他的探究过程中存在的问题是_______________________________.

(3)小华将弹簧测力计一端固定，另一端钩住长方体木块A，木块下面是一长木板，如图乙所示，实验时拉着长木板沿水平地面向左运动，读出弹簧测力计示数即可测出木块A所受摩擦力大小．在木板运动的过程中，以下说法正确的是  （   ）

A．木块A受到的是静摩擦力

B．木块A相对于地面是运动的

C．拉动速度变大时，弹簧测力计示数变大

D．木块A所受摩擦力的方向向左

偏心夹具机构的主要特点是（）

A.自锁性较好

B.操作快速简便

C.扩力倍率大

D.在振动工况下夹紧力稳定

呈球形或五角状扁球形，表面暗黄绿色，顶端有五角星状裂隙的药材是（）

A.巴豆

B.豆蔻

C.吴茱萸

D.葶苈子

E.沙苑子