shì zài bì xíng
勢在必行
to be imperative (under such a circumstance);
勢
shì
n. trend在
zài
adv. in process of必
bì
v. must行
xíng
v. to do/take action
Example
Xuéxí yìménxīnyǔyán shì shìzàibìxíng de.
學習一門新語言是勢在必行的。
Learning a new language is imperative.
學習
xuéxí
v. to learn
語言
yǔyán
n. language