Without corroboration from forensic tests it will be difficult to prove that the suspect is guilty.

没有法医化验的确证就很难证明嫌疑犯有罪。

youdao

Even when a side effect is suspected, it can be very difficult to prove that it was directly caused by the drug.

即便有时察觉到由副作用，也很难证明它是由药物直接引起的。

youdao

Until the 20th century, it was difficult to prove that a particular man was the biological father of a particular child.

在20世纪以前，想要证明某一特定男子是某一特定孩子的生父非常困难。

youdao

But it will also be difficult to prove that North Korea is definitely lying about the uranium.

ECONOMIST: North Korea's nuclear programme

Since it will be difficult to prove that fraud drove down a stock's price, they might be able to hide from scrutiny.

FORBES: Legal

In practice, however, it is difficult to prove that an asylum seeker showing up on Britain's doorstep first entered Europe through France.

ECONOMIST: Refugees