用方框中所给单词的适当形式填空，使短文完整正确（每个单词限用一次）

     Mr. Smith____  from the England. He is an English teaher in NO.8 Middle School. He doesn't know much____ . Does he like____  it? Sure, he____ . He____ to Chinese classes every week. Look! He____ Chinese now. He____  working in China very much. He can____  about something in Chinese now.He____ the Chinese people____  very friendly.

28a⁴b²÷7a³b=____．

如图所示，abc是光滑的轨道，其中ab是水平的，bc为与ab相切的位于竖直平面内的半圆轨道，其半径R=0.30m．质量m₁= $\frac{\sqrt{14}}{10}$ kg的小球A静止在轨道上，另一质量m₂=0.60kg的小球B以水平速度v₀=2 $\sqrt{14}$ m/s与小球A正碰．已知相碰后小球A经过半圆的最高点c落至轨道上距b点为l=4 $\sqrt{2}$ R处，重力加速度g取10m/s²，求：

    The summer holiday is coming. Here are my plans for the summer holiday.

    I'm sure I will spend a meaningful holiday.