重點講解：
1. be supposed to do sth.
應當，應該，須做某事；
eg. She was supposed to be speaking about sales figures, but she kept wandering off the subject.
她本該談論銷售數字，但她老是跑題。
eg. You are not supposed to gull your friends.
你不應該欺騙你的朋友。
2. knock on
敲；擊；
eg. Please do not enter before knocking on the door.
進來前請先敲門。
eg. He went up the garden path to knock on the door.
他穿過花園小徑去敲門。
3. fly into
突然爆發（壞脾氣）；突然陷入（恐慌）；
eg. Losing a game would cause him to fly into a rage.
輸掉一場比賽會讓他暴跳如雷。
eg. In fact, she was not a woman who would fly into a passion.
事實上，她不是那種動輒發火的人。