—This physics problem is too difficult. Can you show me _______, Li Lin?
—Of course.
A:what to work it out
B:what to work out it
C:how to work it out
D:how to work out it
说理:____.
阅读下面这宋词,完成小题。
途中
赵汝鐩
雨中奔走十来程,风卷云开陡顿睛。双燕引雏花下教,一鸠唤妇树梢鸣。
烟江远认帆樯影,山舍微闻机杼声.最爱水边数株柳,翠条浓处两三莺。
已知点G是△ABC的重心,AG→=λAB→+μAC→λ,μ∈R若∠A=120°,AB→·AC→=-2,则AG→的最小值是( )