问题
选择题
At present ________ of the experiments ________done in labs after the new building has been finished.
A．four fifth; is
B．four fifths; are
C．four fifth; are
D．four fifths; is
答案
答案：B
答案 B [考查分数的表达方法。of后面的名词是可数名词复数，因此谓语动词要用复数。]