用来测定发动机输出功率的仪器叫做（）。
参考答案：测功仪
.________ by the advances in technology, many farmers have set up wind farms on their land.
A．Being encouraged
B．Encouraging
C．Encouraged
D．Having encouraged
除去下列物质中的杂质，所用试剂正确的是（ ）
A．①
B．②
C．③
D．④
