index part

例句：

1. 1. The index finger on my left hand points to the right.
   我左手的食指指向右边。
2. 2. This index card has all the information about the meeting.
   这张索引卡上包含了会议的所有信息。
3. 3. The index of a book is the first page of the book.
   一本书的索引是书的第一页。