预防性传播疾病的最好方法是（）

A.推迟首次性行为的时间

B.避免与患有性病的人接触

C.减少性伙伴

D.坚持正确使用避孕套

E.有病要及时治疗

Sam managed to keep in________contact with his family while he was working in New Zealand.

A．pleasant

B．confident

C．constant

D．different