新加坡是亚洲的发达国家，被誉为“亚洲四小龙”之一，其经济发展以（）为主？
A.电子、石油化工
B.金融、航运、服务业
C.博彩
参考答案：A, B
I lived with my sister this summer and didn’t have to pay rent. So I __________ save most of my salary.[ ]
A. could
B. would
C. was able to
D. should
基因型频率
