问题
选择题
He has proved his courage in the battle.
Through tests time and time again, this kind of rope____strong.
A．was proved
B．has ben turned out
C．turned
D．proved
答案
答案：D
考查系动词用法。句意：通过一次次实验，结果证明这种绳子是结实的。turn out,prove作为证明是，结果是，原来是为系动词，无被动语态。