题目

He has a part - time job and was paid___________. A. by the hour    B. by an hour    C. by hour        D. each hour 答案：A 解析: 意指“按小时付钱”。B和c两个表达方式都不对，D不合句子意思。近代西方科学成就、发明层出不穷，下列重大发明出现的先后顺序是①达尔文发表《物种起源》②瓦特开始改良蒸汽机③“日心说”的发明A.③②①B.③①②C.②①③D.①②③