My pen is missing. I can’t find it anywhere.—I’m afraid you have to buy _________.

There are many trees on ________ side of the street.

下列各句中加点成语的使用，正确的一项是（ ）

Martin Van Buren was the eighth president of the United States and the first ______native language was not English but Dutch.

Thank you for ______________ me about it.