用方框内单词的适当形式填空。
explorer,mark,man-made,system,method |
1. The of success is to study hard.
2. There are many in the world. They are
exploring the mystery of the nature.
3. A lot of satellites have been sent up into the space.
4. The computer doesn’t work because there is something wrong with its .
5. It’s impolite for some visitors to leave on the wall of many places of interest.