We need to conduct extensive background research on the firms from

单选题 We need to conduct extensive background research on the firms from __________we received bids.

A．which
B．where
C．that
D．when

参考答案A

解析: 通过选项可以知道此题为选择恰当的关系代词的问题。介词from之前的结构为“主语+动词+宾语”，从而可以知道，from后面的部分为修饰先行词firms的关系代词从句。

单选题 The director decided to delegate some of the work to a subcontractor after his employees __________help with the project.

A．inquired
B．requested
C．asked
D．insisted

单选题 Employees__________ to transfer to the new branch office will receive reimbursements for all moving expense, as well as a bonus.

A．direct
B．directed
C．directing
D．direction

单选题 Support structure under the Main St. bridge have corroded__________ faster than the bridge's designer had predicted.

A．a lot
B．so too
C．very
D．real