选出与其它三个发音不同的选项。
( 1 )____ A. cinema B. coat C. cool D. cup
( 2 )____ A. dance B. rice C. class D. nice
( 3 )____ A. juice B.ice cream C. cinema D. cake
( 4 )____ A. race B. book C. cook D. car
____ ____ brother ____ a Chinese lesson today?
____, he ____.
如图,已知线段AB=8cm,点C是AB上任一点,点M、N分别是AC和CB的中点,则MN的长度为