下列短文，从每题所给的四个选项（A、B、C和D）中，选出最佳选项。
A

School Policy ◆Fighting, saying bad words and all other bad behavior will not be allowed. ◆Do not throw rocks, snowballs, sticks, waste paper or dirt on the school grounds. ◆Rollerblading (直排轮滑) is not allowed at school. ◆Contact through a note or a phone call must be made to the school if you are absent from school. ◆Parents and visitors are required to check in at the office when entering the school.

Lunchroom Guide ◆Students should use quiet voices in the lunchroom. ◆Students should go through the lunch line in a quiet and orderly manner. ◆Students should clean up their eating area before leaving the lunchroom.                                  Meal Prices Lunch: $1.5 daily          Weekly Lunch Ticket: $7.50 Breakfast: $0.80           Weekly Breakfast Ticket: $4.00 Extra meal: $0.45          Adult Lunch: $2.50

根据提示，修改下面一段文字。

    ①人无论在多么困难的情况下都应该想到帮助别人。②我们或许并不是富人，也不是强者，但我们同样能对他人穷苦的处境给予同情，并力所能即地提供一些实际的帮助。③即使微不足道，也足以温暖曾经寒冷的心。④人生的幸福，就在于是否能够相互搀扶。

已知下列反应：①NH₃+H⁺=NH₄⁺  ②Ag⁺+2NH₃=Ag(NH₃)₂⁺ ③Ag⁺+Cl^-=AgCl
前者都比后者更容易发生。下列事实或现象预期错误的是

使用弹簧测力计时，首先要看清它的____，加在弹簧测力计上的力不能超过它的____。测量时，应先提住上端的圆环，使弹簧测力计自然悬垂在____方向上，观察指针是否指在____刻度位置，然后将被测物体挂在弹簧测力计末端的挂钩上。如图所示的弹簧测力计，它的量程是____，最小刻度值是____，物体对弹簧测力汁的拉力为____。弹簧测力计的刻度是均匀的，这是因为在弹簧测力计的测量范围内，弹簧的____与其受到的拉力成正比。

下列句子中，没有语病的一项是（   ）