This building is ________ one in our hometown and it has been there for 70 years.
A:old
B:older
C:the oldest
下列对使用过的塑料制品说法正确的是( )
如图甲所示,长方体金属块在细绳竖直向上拉力作用下从水中开始一直竖直向上做匀速直线运动,上升到离水面一定的高度处.图乙是绳子拉力F随时间t变化的图象,取g=10N/Kg.根据图象信息,下列判断不正确的是( )