通过抑制二氢叶酸还原酶，阻碍疟原虫核酸合成的药物是（） A.氯喹 B.乙胺嘧啶 C.

I`m Tony. My best friends are Frank and Cindy. We often do many things together. Frank lives next to my home and we are in the same class. He is thirteen years old and tall and medium build. He has curly hair and blue eyes. He is good-looking and clever. He is good at math and often helps me with my homework. He likes wearing black pants and yellow T-shirts. Cindy doesn`t go to my school. She is eleven years old. She is thin and medium height. She has curly blonde hair and her eyes are brown. She is good-looking, too, but a little bit shy. She is good at playing the guitar. Her facorite subject at school is music. She often teaches Frank and me to play the guitar after class.

The three of us have great fun together, and we help each other and sometimes play video games at my house.

小题1:        eyes are blue.

A．Frank’s

B．Cindy’s

C．My

D．Tony’s小题2:     good at math .

A．Cindy is

B．Tony is

C．Frank is

D．I am小题3:      is good-looking ,but a little bit shy .

A．Frank

B．Cindy

C．Tony

D．My friend小题4:Where do they play video games ?

A．at school

B．at Frank’s house

C．at Cindy’s house

D．at Tony’s house小题5:What things do the three children do together ? They      .

A．play baseball

B．play video games

C．play the guitar

D．both B&C

下列都属于单细胞生物的是（　　）

A．草履虫和酵母菌

B．草履虫和病毒

C．酵母菌和小麦

D．衣藻和鼠

用托盘天平测量铜块质量时，应将天平放在______桌面上，游码移到标尺的零刻度处，若天平的指针静止在图甲所示位置，则可将平衡螺母向______（选填“左”或“右”）调节，使天平平衡．测量中，当右盘所加砝码和游码位置如图乙所示时天平平衡，则该铜块的质量为______g．