根据下列句子及所给单词的首字母写出所缺单词。在填写答卷时，要求写出完整单词。
66. David can r__________ very fast. I’m sure he will win the race at the sports meeting.
67. It’s dangerous to swim in the r___________. It’s safer to go to the swimming pool.
68. Animals are useful. For example, we can get fresh m__________ from cows.
69. Your voice is very sweet. Would you s_________ a song at the English party?
70. Yao Ming, one of China’s best ever basketball player, is more than 2 meters t________.