It is hard to believe that she's only nine.

很难相信她只有九岁。

《牛津词典》

It is hard to believe that he used to have many problems in school.

很难相信他曾经在学校遇到过很多问题。

youdao

It is hard to believe that years ago, somebody else would just put her on medication (药物治疗) and tell her to calm down.

很难相信，多年前，别人只会让她吃药，告诉她要冷静下来。

youdao

The artist carved her flowing clothing with such detail it is hard to believe she is made of stone.

VOA: special.2010.06.23

Saying that one of them is Napoleon and the other one isn't seems very hard to believe.

说其中一个是拿破仑,另一个不是拿破仑，似乎都难以令人信服。

耶鲁公开课 - 死亡课程节选

Some of his silkscreen prints are so detailed it is hard to believe they are not paintings.

VOA: special.2009.09.02

It is hard to believe this bedridden invalid was once a national skiing champion.

NPR: Many Chinese Athletes Find No Glory In Retirement

It is hard to believe that recent events would not have further eroded European consumer sentiment.

FORBES: Has A Serious Mobile Phone Slump Started In Europe?

However, it is hard to believe that GSK bought Sirtris for the promise of anti-aging compounds.

FORBES: Getting The Benefits Of Red Wine From A Pill? Not Likely.