He made experiments to prove his theory, and the number added up to 600.
A. a large number of ;have
B. a great deal of; has
C. a great many; has
D. plenty of; have
网友回答
A. a large number of ;have
B. a great deal of; has
(答案→)C. a great many; has
D. plenty of; have
解析：考查词组辨析和主谓一致：第一空experiments为可数名词，用a large number of（许多的，大量的）的修饰；第二空the number 为……的数目，做主语时是单数形式，因而用has。选C。