A:﹣1
B:4
C:﹣1或4
D:﹣4或1
中国科学院院士张青莲教授主持测定了铕、铱等近十种元素的相对原子质量,为相对原子质量测定作出了卓越贡献,下列关于铕的说法中正确的是( )
-–Why not get your husband a new energy car for his birthday?
—_______ That's too expensive.