hard有艱辛，艱難的意思，hard是努力的，hardly是幾乎不，后者是固定詞語來的，并不是hard的副詞形式，也就是說是兩個毫無關系，且不同意思的詞，記住就行了。

hard as nails 鐵石心腸; 冷酷無情

as hard as nails 鐵石心腸; 冷酷無情

hard as the nether mill stone 鐵石心腸; 冷酷無情

as hard as the nether mill stone 鐵石心腸; 冷酷無情

be hard done by 受到不公平待遇

be hard hit 受到嚴重打擊(經濟上損失或失去親人等)

be hard on 接近, 緊跟著; 使...難堪; 磨得歷害

be hard upon 接近, 緊跟著; 使...難堪; 磨得歷害

be hard pressed 被逼得很緊, 處于無奈; 被追擊

be hard put to it (做某事)有很大困難; 正在為難, 不知所措

be hard put to do sth. (做某事)有很大困難; 正在為難, 不知所措

be hard up against it [美口]處境很難; 面臨 種種困難

have it hard [美口]處境很難; 面臨 種種困難

bear hard on 拼命壓迫

die hard (習慣等)不易改掉

follow hard after 緊緊跟著

go hard with sb. 使某人遭受不幸[痛苦]

go ill with sb. 使某人遭受不幸[痛苦]

play hard to get 假裝(對某人某事)不感興趣(以等待別人說服)

run sb. hard 緊追某人