"a difficult task"
"nesting places on the cliffs are difficult of access"
"difficult times"
"why is it so hard for you to keep a secret?"
"took a hard look"
"a hard bargainer"
"strong winds"
"a hard left to the chin"
"a knockout punch"
"a severe blow"
"worked their arduous way up the mining valley"
"a grueling campaign"
"hard labor"
"heavy work"
"heavy going"
"spent many laborious hours on the project"
"set a punishing pace"
"unvoiced consonants such as `p' and `k' and `s'"
"Russian distinguished between hard consonants and palatalized or soft consonants"
"a hard drinker"
"hard liquor"
"had hard luck"
"a tough break"
"hard dry rolls left over from the day before"
"the team played hard"
"worked hard all day"
"pressed hard on the lever"
"hit the ball hard"
"slammed the door hard"
"held hard to the railing"
"thought hard about it"
"stared hard at the accused"
"industries hit hard by the depression"
"she was severely affected by the bank's failure"
"prejudices die hard"
"he drank heavily"
"concrete that sets hard within a few hours"
"it stands hard by the railroad tracks"
"they were hard on his heels"
"a strike followed hard upon the plant's opening"
"he took the rejection very hard"
"hard alee"
"the ship went hard astern"
"swung the wheel hard left"
This is a hard question to answer.
这是个难题,不好回答。
This food is hard of digestion.
这个食物很难消化。
It is hard, if not impossible.
这个表达是错误的。