Lucy, Jim and Li Lei ____good friends.[ ]
A. is all
B. are all
C. all is
D. all are
B
一个边长4厘米的正方形,最少要用16厘米长的铁丝才能把它围一圈.______.
随年龄增长,心脏的变化有()
A.重量增加
B.排出量减少
C.信指数增加
D.心肌收缩期缩短
E.收缩力减弱