问题
选择题
The construction of the two new railway lines by now.
A．have been completed
B．has been completed
C．has coompleted
D．have completed
答案
b
B。考查动词时态和语态。由时间状语by now直到目前为止可知应该用现在完成时，铁路线与建完之间是被动关系所以要用被动语态的现在完成时，句子的主语是抽象名词短语，用单数谓语因此B是正确答案