第一句:The teacher (主语) is (系动词) a very enthusiastic woman (表语) called Ms Shen.(定语) (= 那位老师叫沈老师,是一位热情的老师);
第二句:Today (状语)we (主语) introduced (谓语) ourselves (宾语) to (介词) each other (介词宾语) (= 今天我们相互进行了自我介绍);
第三句:We (主语) work (谓语) by ourselves (状语)(= 我们独自工作).