Underdeterminant
子行列式
??? 情景例句
This job is no picnic.
這份工作很累人。
I'm afraid you will catch a cold.
我怕你會感染到感冒。
Many firms, for instance, have great difficulty in obtaining technical or scientific books from libraries
比如，很多公司向圖書館借閱科技書籍時感到很困難，