what if 用法what if 要是…… 会怎么样呢what if +主语+谓语火车要是晚点怎么办?汽车抛锚what if the train is late ?要是她忘记带来会怎么样？what if she forgets to bring it ?万一我病了怎么办呢？what if I should fall ill ?如果汽车抛锚了怎么办？what if the car breaks d...