Choose the right words, phrases or sentences to fill in the blanks: They have studied_______six o'clock: a. in; b. at; c. since; d. for

Choose the right words, phrases or sentences to fill in the blanks
They have studied_______six o'clock 
a. in 
b. at
c. since 
d. for
My mother was _______ last night, so we went out for dinner.  
a. tired enough to cook b.  too tired to cook 
c. very tired to cook
d. tired for cook
 The new shopping mall is quite _______ the present shopping area.
a. different from
b. the same 
c. like to 
d. similar
_______have you lived in this town? - For nearly 20 years.
a. How much
b. How many 
c.  How far 
d.  How long 
They _______ a holiday for ten years.
a. haven't had 
b. didn't had 
c. don't have 
d. aren't having 
Airmail  is _______ expensive than surface mail.
a. the most
b. the same
c. as 
d. more 
 It's two years since I last _______ Joe.
a. see
b. saw 
c. have seen 
d. community 
They're offering a 10%_______on all sofas this month. 
a. reward 
b. discount 
c. reduce 
d. cut
''______________'' -  ''It's 20.000 dong."
a. How much is this parcel cost?
c. How much is this parcel?
b. How much does this parcel take?
d. How much does this parcel worth?