阅读下面短文，从各题所给的A、B、C、D四个选项中选出最佳选项。
B
Join Us for a Day at Sun Valley Amus ement Park

    Children aged 10 to 14 are invited to take part in the "Event of the Summer" at
Sun Valley Amusement Park, the most popular amusement park on the East Coast.
Sun Valley has more than 80 amusement rides. For sports lovers, there are
basketball courts, an indoor baseball field and climbing walls.
    No amusement park would be complete without a gift shop. Sun Valley
has two.
    You won't want to miss out on this day of fun. Join us at Sun Valley Amusement Park on July 14. Register (登记) early.
    • The cost of the trip is $ 25. This includes tickets and all rides.
    • We suggest that all children bring lunch.
    • Buses leave at 9.00 AM and return at 5.00 PM.
    • Rain Date: Wednesday, July 16.
    Register at the Children's Recreation Center at the Town Hall by July 3.
    A one-day registration will also be held on July 1 at the Brown School.
    For more information, call Jane Parks at 555-7267.

若分式 $\frac{x^2-4}{x-2}$ 的值为0，则x=____；分式 $\frac{x\left(x+2\right)}{5\left(x+2\right)}$ = $\frac{x}{5}$ 成立的条件是____

推动物理课本在小桌面上做匀速直线运动，物理课本共受____ 个力的作用，其中除推力和受到的摩擦力是一对平衡力之外，还有受到的____ 力和____ 力是一对平衡力．

图片是形象的史料,下列图片反映的历史事件按时间先后排序正确的是（   ）

左图到右图的变化，反映的本质问题是（    ）