______ you eat the correct foods ______ be able to keep fit and stay healthy. [ ]

A. Only if; will you

B. Only if; you will

C. Unless; will you

D. Unless; you will

日本许多汽车行业的知名企业纷纷到美国投资建厂，是因为美国

A．国土辽阔，资源丰富

B．经济发达，汽车市场广阔

C．生产成本低，规模效益大

D．汽车生产技术落后于日本