如图所示,电路元件及导线连接均完好,闭合开关S1、S2,则( )
A:L1不能发光,L2能发光
B:L1能发光,L2不能发光
C:L1、L2都能发光
D:L1、L2都不能发光
Our teacher often asks us ____________ questions in groups.