Tom: Hello! My name is Tom. What's your name?
Lily: My name is Lily.
Tom: Are you new?
Lily: Yes!
Tom: What class are you in?
Lily: I'm in Class 1, Grade 6.
Tom: Me too.
Lily: Can you show me our classroom?
Tom: OK! It's on the 3rd floor.
人体内某种细胞的形状可近似看作球体,它的直径为0.0000156m,则这个数用科学记数法表示为____ (保留两个有效数字).
雨后的夜晚,当你迎着月光走在有积水的路上,为了避让水洼,应走“较暗”的地面.这是因为光在( )
“中共八大”、“国民经济的调整”、“文化大革命”共同反映出的时代主题是( )
水分和无机盐能够运送到大树顶端,拉力的产生主要是靠( )