第一台电子数字计算机于()年问世
A.1945
B.1946
C.1948
D.1950
参考答案:B
Sorry, there is no Yangzhou Fried Rice now. It _____ only for lunch and supper.
A.serves
B.served
C.is served
D.is serving
筛选是根据药物与杂质的哪项性质不同来分离药物中的杂质()
A.比重
B.体积
C.浮力
D.色泽
E.气味