[求助]几道第一套涛涛数学里的题

Q10:

A
set of numbers has the property that for any number t in the set, t + 2 is in
the set.  If –1 is in the set, which of
the following must also be in the set?

I.                    
-3

II.                  
1

III.                 
5

A.    I
only

B.    II
only

C.    I
and II only

D.    II
and III only

E.    I,
II, and III

答案选的是D，很不能理解为什么E错了？

Q16:

If
J, S, and V are points on the number line, what is the distance between S and
V?

(1)     The distance between J and S is 20.

(2)     The distance between J and V is 25.

A.
Statement (1) ALONE is sufficient, but statement (2) alone is not
sufficient.

B.
Statement (2) ALONE is sufficient, but statement (1) alone is not
sufficient.

C.
BOTH statements TOGETHER are sufficient, but NEITHER statement
ALONE is sufficient.

D.
EACH statement ALONE is sufficient.

E.
Statements (1) and (2) TOGETHER are NOT sufficient.

不能理解答案为什么会选E？

Q30:

Joanna
bought only $0.15 stamps and $0.29 stamps. 
How many $0.15 stamps did she buy?

(1)     She bought $4.40 worth of stamps.

(2)     She bought an equal number of $0.15 stamps
and $0.29 stamps.

A.
Statement (1) ALONE is sufficient, but statement (2) alone is not
sufficient.

B.
Statement (2) ALONE is sufficient, but statement (1) alone is not
sufficient.

C.
BOTH statements TOGETHER are sufficient, but NEITHER
statement ALONE is sufficient.

D.
EACH statement ALONE is sufficient.

E.
Statements (1) and (2) TOGETHER are NOT sufficient.

http://forum.chasedream.com/dispbbs.asp?boardID=22&ID=184062&page=1

以前讨论过了，这两题都很阴险的，自己也做错了

Q16:

If
J, S, and V are points on the number line, what is the distance between S and
V?

(1)     The distance between J and S is 20.

(2)     The distance between J and V is 25.

A.
Statement (1) ALONE is sufficient, but statement (2) alone is not
sufficient.

B.
Statement (2) ALONE is sufficient, but statement (1) alone is not
sufficient.

C.
BOTH statements TOGETHER are sufficient, but NEITHER statement
ALONE is sufficient.

D.
EACH statement ALONE is sufficient.

E.
Statements (1) and (2) TOGETHER are NOT sufficient.

这道题目答案给的是E。LS给的连接没有16题的解释哎~~~所以还要问下~