根据句意和首字母提示补全单词。

66. Mr. Smith can o_____ his guests some coffee or tea when they come to his home.

67. Today, everyone o_____ to be a greener person.

68. I felt a sharp pain in my c_____.

69. He is the s_____ of person who only cares about money.

70. We must remember that n_____ of us is infallible (永无过失的). We all make mistakes.