单项选择题
A．back B．in C．for D．against
Once he set his mind to（）something, he would not give u...
单项选择题Once he set his mind to（）something, he would not give up easily.
A．do B．doing C．be doing D．having done
By（）your work environment and personal practices, you m...
单项选择题By（）your work environment and personal practices, you may be able to reduce fatigue and discomfort.
A．adapt B．having adapted C．adapting D．being adapted
The commercial purpose of a trade mark is（）the goods or...
单项选择题The commercial purpose of a trade mark is（）the goods or services of a company from those of competitors.
A．to distinguish B．having distinguished C．distinguishing D．being distinguished
