Hard的近義詞有哪些

Hard的近義詞有:

difficult，firm， solid

It must be very difficult at sea， too .海上的日子想必也很不好過吧。

Doing so may be difficult in practice .在實踐中這樣做可能會有困難。

It is difficult to obtain reliable evidence .這很難取得可靠的憑據。

The contact resistance is difficult to measure .接觸阻力很難測量。

The book is too difficult for me to read .這本書太艱深，我讀不下去。