Chọn đáp ấn đúng : 1 , The countryside air is fresh ; ............... , it's not polluted . a , however b , whenever c , moreover d , beside 2 , ........... she spoke slowly , I don't understand her . a , since b , although c , if d , as 3 , People find the water dirty ................. there are some waste chemicals in it . a , and b , as c , but d , where 4 , .............. you smoke too much , you'll get respiratory problems . a , if b , though c , as d , because 5 , If she ............... hard , she will break past records and set new ones . a , try b , will try c , tries d , tried 6 , ............. it is rainy , I walk home with my umbrella . a , when b , though c , but d , because 7 , The kids didn't go to the movie last night ............... it rained very heavily . a , and b , but c , as d , now 8 , The air polluted .............. the factories produce a lot of smoke . a , and b , however c , since d , but 9 , Children should drink milk ........... it's good for their health . a , and b , as c , but d , not 10 , John was ill , ........... he went to bed early . a , but b , so c , because of d , however 11 , I'd love to play the table tennis ................ I have to complete an assignment . a , and b , so c , but d , or 12 , He likes to travel , ............. so does she . a , and b , or c , but d , therefore