根据句意及汉语提示写出单词,每空只限一词。
When his father               (到达) London, he went to see the Big Ben.
He is interested in playing football . ________________ (然而), his brother likes basketball.
The students will have a school trip at the _________________(开始) of the month.
He is an important official(官员) in the ______________ (政府).
It is necessary for everyone to know the ______________( 重要 ) of wetlands.