即时跟踪1　 用所给动词的正确形式填空 1．—Where is Mary? —She is still in the lab.She _____________(do) the experiment since this morning. 2．It __________________(rain) for two days.When will it stop？I'm eager to go out. 3．The foreign scientists __________________(work) in our college for eight years and they don't have the intention to leave.

has been doing

has been raining

have been working