—Did you have a good time?
—It couldn't be worse. We were held up on the expressway for three hours. On the way back, we found the car got a f____ tyre, and the spare was, too.
下列有关二氧化碳的检验、制备和用途能达到目的是（ ）
临时装片出现了气泡，这主要是哪个操作步骤不符合要求( )
赏：____
