-What are you going to do this weekend ?-- Im going to do some outdoor activities

问题补充：

---- What are you going to do this weekend ?

---- Im going to do some outdoor activities it rains .

A. If B. unless C. because

答案：

解析：句意：这个周末你打算做什么？如果不下雨我打算做一些户外活动。A如果B如果不C因为。根据句意，故选B