问题
选择题
Working hard is not only a _____ of great success, but it is among the essential requirement.
A．sign
B．singal
C．guarantee
D．expectation
答案
答案：C
句意：勤奋工作不仅仅是巨大成功的保证，它还是基本要求之一。A. sign符号、标志；B. singal 信号；C. guarantee保证；D. expectation期待。由句意可知选C。
考点: 考查名词的用法。