【題目】You should speak _______at table in western countries.

【題目】I don’t know ______ you are right or not.

【題目】The accident is (serious)than we think.

【題目】The population of this town is (increase)by five percent every year.

【題目】We will go there next Saturday unless it _______.

【題目】I ______ play the piano when I ______ four years old．

【題目】You must ______a plan as quickly as possible.

【題目】The _______of living in that city is very high．