My brother is going _________ to be a doctor.
A：study medicine
B：to study medicines
C：to study medicine
D：studying medicine
用适当的介词填空
（1）He was born____ a cold morning.
（2）The girl began to learn to play the piano____ an early age.
（3）The beautiful music was____ Gu Jianfen.
（4）We often watch concerts____ TV.
（5）The boy can play all types____ instruments(乐器).
化学上把“生成新物质的变化叫做化学变化”,下面对化学变化中“新物质”的解释，正确的是 ( )
下列各项产业群项目中，不属于化学研究范畴的是（ ）
