clam up
/klæm/
to become silent suddenly, usually because you are embarrassed or nervous, or do not want to talk about a particular subject
(通常指因爲尴尬、緊張或不願談論某一話(huà)題而突然)沉默不語，閉(bì)口不言 ，拒不開口
He just clams up if you ask him about his childhood.
要是你問起他的童年，他就幹(gàn)脆不吭聲瞭(le) 。
He's hiding something. He clams up every time we try to ask him about Mary.
他在竭力隐瞞什麽東(dōng)西 。每次問他瑪麗(lì)的事他都支支吾吾。
