如图是一个三棱柱，它的左视图是（ ）
A：
B：
C：
D：
Here you ____ (is/are).
若一元二次方程ax2﹣bx﹣2015=0有一根为x=﹣1，则a+b=____
— Are the beaches in Dalian beautiful?
— Sure. They lots of tourists from home and abroad every year.
