题目

把锌片和铁片放在盛有稀食盐水和酚酞试液混合溶液的玻璃皿中，经过一段时间后，首先观察到溶液变红的区域是( ) A．Ⅰ和Ⅲ附近  B．Ⅰ和Ⅳ附近 C．Ⅱ和Ⅲ附近  D．Ⅱ和Ⅳ附近 答案：B It is only in the last sixty years that________any evidence that Loch Ness Monster might exist.        A．there has been  B．there was  C．it has been       D．it had