Question

It is (believe)_____________that you have been 56 years old. You look much younger than that.

Answer 1

unbelievable

【译文】实在难以相信你已经56岁了，你看起来要比实际年龄年轻。

【考点】同性转换

【解析】由后一句“you look much younger than that”可知，前一句的意思应该是“难以置信你已经56岁了。”在句中作表语且表否定，因而要用unbelievable。