9 A hard worker is a happy worker.

This room ought __________ before five o’clock. A: to clean B: clean C: be cleaned D: to be cleaned

you already your room? -Yes.I it two hours ago A: Did, clean; cleaned B: Did, clean, have cleaned C: Have, cleaned; cleaned Have, cleaned; have cleaned

A firm will hire a worker whenever that worker's marginal product of labor is:() A: greater<br/>than the marginal product of labor for the next best worker. B: less<br/>than the marginal product of labor for the next best worker. C: greater<br/>than the worker's wage. D: less<br/>than the worker's wage.

On a production function, as capital per worker increases, output per worker A: increases. This increase is larger at larger values of capital per worker. B: increases. This increase is smaller at larger values of capital per worker. C: decreases. This decrease is larger at larger value of capital per worker. D: decreases. This decrease is smaller at larger value of capital per worker.