在参加该项目之前必须结清余账。You have to pay your outstanding bill before joining the scheme.在拿吃的之前，用热肥皂水把手好好地洗干净。Wash your hands thoroughly with hot soapy water before handling any food.在1918年再版之前，这本书一直非常罕见。It remained an exceptional...
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...