题目

It seemed that we had experienced four seasons in a day. (句型转换)We seemedfour seasons in a day. 答案：【1】to【2】have【3】experienced为庆祝祖国六十华诞，某单位排练的节目需用到如图所示的扇形布扇，布扇完全打开后，外侧两竹条AB，AC夹角为120°，AB的长为30cm，贴布部分BD的长为20cm，则贴布部分的面积约为    cm2（π取3）