Cook was a strict but good captain who usually took care of the sailors on his trip

问题补充：

Cook was a strict but good captain , who , usually , took care of the sailors on his trip .

A. the one

B. one

C. that

D. this

答案：

A. the one

(答案→)B. one

C. that

D. this

解析：考查代词，the one特指前面的可数名词单数，one泛指前面的可数名词，that代指前面的可数名词单数，或是不可数名词，this指代下文，句意是：Cook是严格的但很好的船长，一个通常在航行中照顾水手的船长，one指代a captain。选B。