1. Don't touch anything ____________ your teacher tells you to.
A. if B. Unless C. since D. when
2. About ____________ of the books in our school library are written in Chinese.
A. four-fifth B. four-fifths C. fourth-fifths D. fourths-fifth
3. No one can be sure ______________in a million years.
A. what man looks like B. what will man look like
C. what man looked like D. what man will look like
