硒和铝在生物中含量其微.Selenium and aluminum are found in vanishingly small concentrations within living things.除了硒和汽相沉积的锗和硅之外, 玻璃至少是二原子的.Apart from selenium and vapour - deposited germanium and silicon, glasses are at least diatom...
Most have slavishly copied the design of IBM'sbig mainframe machines.大多数公司都一味模仿IBM公司大型主机的设计。Instructors read slowly and students copied down what was said.老师慢慢地念，学生们把所念的记下来。Tape is expensive and loses sound quality ...