A local wind which occurs during the daytime and is caused by the different rates of warming of land and water is a（）.

单项选择题A line on a weather chart connecting places which have the same barometric pressure is called an（）.

A.isotherm
B.isallobar
C.isobar
D.isotope

单项选择题A feature of an inflatable raft which helps keep people stationary in rough weather is（）.

A.lashings on the floor of the raft for the passenger's feet
B.straps from the overhead
C.lifelines on the inside of the raft
D.ridges in the floor of the raft

单项选择题A cold front moving in from the northwest can produce（）.

A.thunderstorms，hail，and then rapid clearing
B.increasing cloud cover lasting for several days
C.lengthy wet weather
D.low ceilings with thick cirrus clouds

单项选择题（）rain means it rains in some parts of the area.

A.Squally
B.Isolated
C.Scattered
D.Occasional

单项选择题（）moving rather quickly east expected 150 miles south of Cape Farewell 972 by 160000 GMT.

A.Developed low
B.Developing low
C.Being developed low
D.Low to be developed