-- Tu Youyou received the Nobel Prize for her ________ of anemisinin（青蒿素）.
-- And she was the first Chinese who won the prize in science.
如下图所示的电路，断开开关S1、S2，闭合开关S3，灯L1与L2____ 联；断开开关S3，闭合开关S1、S2，灯L1与L2____ 联。（填“串”或“并”）
