Great changes ____________ in my hometown in the past few years.

A have taken place.　　B. took place　 　C. have been happened　　　 D. were taken place

热电阻是利用物质在温度变化时，本身（）也随着发生变化的特性来测量温度的。

A、电流

B、电压

C、电阻

D、脉动电势