( )是12的质因数.
A.1
B.2
C.4
D.12
12=2×2×3,
质数有2、3,即2、3是12的质因数;
故选:B.
细的量筒的测量结果_____精确。
She always has a smile on her face. What makes her so ? [ ]
A. happily
B. happy
C. sad
D. unhappy