【单选题】The following data are given for labour costs of direct workers in a company for one week. Production hours 380 Idle time hours 20 Special order hours 30 Total hours ...
【单选题】A heavy commitment to a part-time job during the academic year, say, working 20 hours per week or more, undermines and significantly____________ school achievement and commitment.
【判断题】According to the research in Passage 1, about 20 hours per week is the safe amount of working time that done not affect school performance significantly.