单子叶植物根的维管束为辐射型维管束。( )
参考答案：对
—I feel tired and sleepy.
—Why not stop ______? [ ]
A. resting
B. breaking
C. to relax
D. to work
静脉血栓的尾部是
A．白色血栓B．混合血栓C．红色血栓D．透明血栓
