单词拼写（共10小题，每小题1分，满分10分）
61．S______ is the system by which some people are owned by others.
62．Fifty years ago, mixed-race marriages were f________.
63．The police a_____ Rosa Parks, a black woman who refused to give her seat to a white man..
64．Do you know which big cities are at the same a______ as Rio de Janeiro?.
65．There are many café, shops and restaurants on Copacabana’s main a________ .
66．It is very relaxing to take a d______ in the pool in summer.
67．There is a w______ belief among bioengineers that it will be one day be possible to create life under laboratory conditions. .
68．It is easier for a physical wound to heal than a m______ one.
69．Although Sam left school more than ten years ago, he still keeps in touch with his f_____ classmates .
70．Some people are g______ for money and some for power. .