问题
选择题
Questions and exercises are given by the computer, which decides ______ to move the students ahead, review an easier level, ____ give more work on the same level.
A．either, or
B．both, and .
C．whether, or
D．not only, but also
答案
答案：C
Whether---or·---表选择。问题的给出是为了决定是提高水平还是做同一水平的题。故选C。