Lucy will ____ ____ her friend
松赞干布迎娶文成公主是在( )
eat (过去式)____
①____一年沙尘暴总天数最多?是____天?
②____一年沙尘暴总天数最少?是____天?
③十年以来沙尘暴总天数的整体趋势是上升还是下降____?