Two ways to use this expression if you tell someone to clam up, which is a little bit old fashioned, you don't hear people saying that anymore, but you used to hear some teachers that clam up means shut up means close your mouth, stop talking, but if a person clams up, it means maybe they got really nervous and they just, they couldn't speak, So if again in school, if your teacher calls on you to answer a question and you clam up means you get really tight and quiet and don't say anything, you're too nervous.
兩種方式來使用這種表達方式,如果你告訴別人clam up,這是一個有點老式的,你不聽到人們說,現在,但你曾經聽到一些老師,clam up意味著閉嘴意味著關閉你的嘴,停止說話,但如果一個人clam up,這意味著也許他們得到了真正的緊張,他們只是,他們不能說話,所以如果再次在學校,如果你的老師叫你回答一個問題,你clam up意味著你得到真正的緊張和安靜,不說什麼,你太緊張了。