1. I'm having a wonderful time here in Zhangjiajie.我在张家界玩得很开心。
have a wonderful time玩得高兴
have a great (good） time / enjoy oneself 玩得愉快e.g: Sally said that she had a good time ( enjoyed herself)in Beijing last week.
萨莉说她上周在北京玩得很高兴。

2. Some of them look like humans while others look like wildanimals.
它们中的一些看上去像人，另一些像野生动物。some... others....一些……,另一些……
e.g.:Some students are playing games, and others are playingchess.一些同学在做游戏,其他的同学在下象棋。

3. Last night we camped by a small lake.
昨晚我们在一个小湖边宿营。
by a small lake “by...”在一边/旁e.g: I'm standing by the desk.
我站在课桌旁。

4.It woke everybody up.它叫醒了大家。
wake up“叫醒,唤醒”。其中up是副词,代词作宾语置于wake和lup之间;而名词作宾语,既可以置于wake和lup之间,也可以置于up之后。
e.g:She wakes up her daughter every morning.每天早上她叫醒她的女儿。

5.Tomorrow we’re going to Dongting Lake,the second largestfreshwater lake in China.
明天我们将去洞庭湖——中国的第二大淡水湖。the second largest“第二大…--…”
“定冠词 the+序数词+最高级……”表示“第几最……的”
e.g : Yellow River is the second largest river in China.
黄河是中国第二大河。