下列各句没有语病的一项是( )
________ the difficulties, there will also be many exciting things waiting for you.
My old neighbour Charles felt ________ after his children moved out.
以恒定的功率P行驶的汽车以初速度v0冲上倾角一定的斜坡,设受到的摩擦阻力恒定不变,则汽车上坡过程中的v﹣t图象可能是图中的哪一个( )