1.choke的基本意思是指在吃东西时由于咽喉阻塞、堵塞或极度刺激而咽不下去了,即“噎住”,引申可表示河流“阻塞”,人的呼吸“窒息”等。
2.choke表示“哽”“噎”时,是不及物动词; 表示“阻塞”“窒息”时是及物动词,跟简单宾语。

choke back〔down〕(v.+adv.)
抑制 prevent oneself from expressing anger or sadness
〔说明〕 choke back〔down〕常不用于进行体。
▲choke sb/sth ⇔ back/down
When she learned the sad news, she found it hard to choke back her tears.当她得知那个悲痛的消息时,泪水止不住夺眶而出。

choke off(v.+adv.)
▲choke sb/sth ⇔ off
1.中止做; 使放弃做 prevent or stop sth
They'd ruthlessly choked off all opposition to their plans.他们无情地把反对他们的方案都压制下去了。
It was a thankless job, so we choked him off before long.那是一件吃力不讨好的事情,所以我们很快就不让他做了。
2.批评; 责备 discourage sb, as from speaking
◇ 用于be ～ed 结构
He got choked off for being late.他由于迟到挨了批评。

choke up(v.+adv.)
1.使装满,塞满 fill to full
▲choke up
The channel had chocked up with sand so that boats couldn't use it.河床为泥沙所堵塞,船只无法通行。
▲choke sth ⇔ up
The worker quickly cleared away the dirt that was choking up the chimney.那工人很快就把塞住烟囱的污垢清除干净了。
◇ 常用于be ～ed 结构
The garden was neglected so long that it was choked up with weeds.这座花园由于日久荒芜而长满了杂草。
2.因感情冲动说不出话来 become speechless from a strong emotion
▲choke up
He choked up and wouldn't finish his speech.他激动得说不出话来,没法结束他的发言。
When she heard the exciting news, she choked up and couldn't utter a word.当听说那个激动的消息时,她感到喉咙里哽住了,一句话也说不出来。

用作不及物动词
▲S+～(+A)
He choked when he ate his food too quickly.他吃东西太快噎住了。
Mary choked on his drink.玛丽喝饮料时给呛了。
He choked with anger.他气得说不出话来。
用作及物动词
▲S+～+n./pron.
Let go, you choke me!放开呀,闷死我了!
The smoke almost choked the fireman.烟呛得那位消防队员几乎透不过气来。
The gas choked him.煤气使他窒息。
Sand is choking the river.沙子阻塞了河流。
◇ 用于be ～ed 结构
The river is being choked with sand.泥沙正使河道淤塞。