1. Eachworkerputs in nearly 2,200 hours a year, _________ average, and contributes about $ 30 to GDP per hour. （2018-06）A. with B. in C. onD. under2. ______ some degree, all managers who supervise people are involved in HR activities. (2017-12)A. On B. To C. For D. With3. ____ my opinion, customer service here has improved but not as much as expected over the last two years. (2014-06)A.OnB. InC. ForD. With4. We will provide you with tips to help you keep your stress levels ______ control. (2013-12)A.forB. onC. underD..with