Meaning of zhí xiàn:
zhí xiàn
直线
Noun
straight line
Tā zài zhǐ shàng huà le yī tiáo zhí xiàn.
他在纸上画了一条直线。
He drew a straight line on the paper.
Adverb
sharply (rise or fall)
Gǔshì zài duǎn shíjiān nèi zhíxiàn shàngshēng, ràng tóuzī zhě dàchī yī jīng.
股市在短时间内直线上升,让投资者大吃一惊。
The stock market rose sharply in a short period, startling investors.