辨析下面两句话。

根据下面对话情景，在每个空白处填上一个适当的单词，使对话的意思连贯、完整。

A: Hi, excuse me.

B: Yes. How can I ____  you?

A: I'm new in town. Where is the Science Museum, please?

B: Go along Center Street and ____ right on Main Street. Then you'll see it on your left. It's across from the park.

A: Is it far from here?

B:____ , it's quite far from here. And you can take a bus.

A: Which ____  can I take?

B: The No. 5 bus.

A: Is____ a bus stop near here?

B: Yes, there is. I can walk with you.

A: Oh, that's great! Thanks so much.

B: No problem.

罗斯福在某次《就职演说》中曾说：“我们要前进，我们就必须像一支训练有素而又忠诚的军队那样，为了共同的纪律而乐意有所牺牲：因为没有这样的纪律就不可能前进，就不可能实现有效的领导。”这里他主要是强调（   ）

1916年，美国著名实验物理学家密立根，完全肯定了爱因斯坦光电效应方程，并且测出了当时最精确的普朗克常量h的值，从而赢得1923年度诺贝尔物理学奖．其原理如图甲所示，若测量某金属的遏止电压U_e与入射光频率v的关系图象如图乙所示，图中频率v₁、v₂，遏止电压U_e1、U_e2及电子的电荷量e均为已知，则：