根据汉语提示完成句子。
1. 你最好立刻回去工作.
You _______ _______ _______ _______ _______ _______ at once.
2. 今天我有很多重要的事情要说.
I have many _______ _______ _______ _______ _______ _______ today.
3. 上周末彼得去西安看望爷爷了.
Last weekend, Peter _______ _______ _______ his grandpa in Xi'an.
4. 去年夏天我们全家乘火车去颐和园旅行.
Our family_______ _______ _______ _______ _______ to the Summer Palace last summer.
5. 坐在公交车的二层在城市观光是很惬意的.
It's fun _______ _______ _______ around the city on the second floor of the bus.