旅游是指人们离开惯常环境，到其他地方访问，他的活动连续停留时间不超过 ( )。

A．三个月
B．半年
C．一年
D．两年

One study conducted by a psychologist (121) of interviewing workers before and after the installation of a robot. The robot was used to control a matching process of stamping and assembling metal parts. Prior to installation, much of the work done by skilled machinists. After installation, the robot did the work, but the workers controlled the robot through the robot through a control panel. The results of the study indicated that the workers praised the robot (122) eliminating the physical labor and fatigue (123) the manual operation, but complained of more and continued stress. Prior to installation of the robot, there was time for talking or short periods of relaxation between jobs. Now, however, because of the speed of the robot, there was a need for constant scanning and monitoring of the operation (124) performed by the robot has the installation of the robot created a better work environment Has the change from physical labor to mental stress resulted in an improved (125) of life Much additional research is necessary.

（124）是（）

A.Of

B.consisted

C.for

D.being