I. 单项选择 （共15小题；每小题1分，满分15分）
从A B C D 四个选项中，选出可以填入空白处的最佳选项。
1. _____ tiger, which belongs to _____ cat family, won't attack ______ human being unless too hungry or threatened.
A. A; the; a B. The; the; a C. A; a; the D. The; a; the
2. It is true that mobile phones have made daily communication more convenient but people are also bothered or even annoyed by endless junk _______ from unknown sources. .
A. information B. texts C. messages D. documents
