(40).......................
A.function
B.use
C.aim     
D.purpose

(39)..................
A.to
B.for
C.at
D.in

Why does the author mention tsunamis in the passage? 
A.To explain that not all tides are caused by gravity.
B.To give an example of an extreme tidal phenomenon.
C.C. To show that they are not related to natural tides.
D.To suggest that more categories for tides area needed.

The word exerts in paragraph 2 is closet in meaning to
A.mixes with
B.bring into use
C.infers from
D.connects with

“Why hasn’t Peter phoned? She wondered.
She wondered.......................................
A.
B.
C.
D.

Which of the following does not relate to Ordinary Tides ? 
A.Receiving greatest influence from the Moon
B.Influenced by the Sun’s position relative to the Moon.
C.Taking turns the higher and lower water relating to the Earth’s rotation
D.Having the striking range of tide in narrower bays

Mark the letter A, B, C or D to show the underlined part that needs correction.
A large amount of popular expressions in our language have interesting backgrounds.
A.A large amount
B.expressions
C.have 
D.backgrounds.

Besides ordinary tides , how many other types of tide are mentioned in the passage ?
A.two
B.three 
C.four
D.five

What is true about the Moon’s gravitational force ? 
A.It pulls water on the far side of the Earth more strongly.
B.It is more than twice as powerful as that of the Sun.
C.It has reduced gravity when it is lined up with the Sun and the Earth.
D.Its force is strongest when it is located at 90 degrees to the Earth.

According to paragraph 3 , it is true that
A.Neap tides are characterized by lower water during the low tide period.
B.Spring tides occur when the Moon is in first and the third quarter.
C.The Sun has more gravitational force than the Moon because of it larger size.
D.The range of tide is greater in spring tides than in ordinary tides.