摘要:Lithium (pronounced /ˈlɪθiəm/) is the chemical element with atomic number 3, and is re[阅读全文:]
摘要:Lead Lead (pronounced /ˈlɛd/) is a main-group element with symbol Pb (Latin: plumbum) and a[阅读全文:]
摘要:Letter of creditA standard, commercial letter of credit is a document issued mostly by a financial in[阅读全文:]
