如果a是b的3倍,那么a和b的比是3:4.______.
设b为x,则a是3x,则:
3x:x=3:1;
故判断:×.
阅读理解。
Look at this boy. He is an English boy. His first name is Peter. His last name is Black. His school ID
card number is three-two-eight-six-six-one-nine. His teacher is Miss Smith. Miss Smith is a good teacher. What's that? It's his backpack. It's blue. Where's his pencil-case? It's in his backpack.
根据短文内容,判断正(T)误(F)。
( )1. The boy is Peter Black.
( )2. His school ID card number is 3286699.
( )3. His teacher's last name is Smith.
( )4. His backpack is black.
( )5. His pencil-case is on the desk.
自由降落入水救生艇每()个月至少进行一次搭载额定操艇人员自由降落下水。
A.一
B.三
C.六
D.十二