单项选择题
Besides the electrons, an atom also contains positive electrical particles（）total charge must be equal to that of the electrons.
A．which B．that C．whose D．of which
单项选择题 Where is the article（）you quoted this line
单项选择题 The winner of the Nobel Prize in physics dedicated the honor to his high school physics teacher,（）had been an inspiration during his early years.
单项选择题 We will put off the picnic until next month（）the weather may be better.
