重点讲解：
1. come up
走近；过来；
eg. They had come up from London loaded down with six suitcases.
他们拖着6只箱子从伦敦过来。
eg. He rang for the servant to come up.
他鸣铃叫仆人过来。
2. a long time ago
很久以前；
eg. He must have started writing his book a long time ago.
他一定很久以前就开始写这本书了。
eg. I gave that idea up a long time ago.
我很久以前就放弃那个想法了。
3. of course
（表示通常、显见或众所周知的事实）当然，自然；
eg. Which of course is simply not true.
这当然不是真话。
eg. Of course, slap-bang in the middle of town the rents are high.
当然，市区中心的租金是很高的。