82. Some people can’t tell red _______ green, as there is a

82. Some people can’t tell red _______ green, as there is a fault in their eyes.
a. by b. on c. from d. over
83. When John woke up he was in the hospital, but he didn’t know how that had come ________.
a. about b. around c. by d. across
84. People who live in a small village are bound to see a good _______ of each other.
a. quantity b. amount c. deal d. degree
请问选择哪个?为什么?谢谢!