阅读下面短文, 按照句子结构的语法性和上下文连贯的要求, 在空格处填入一个适当的词或使用括号中词语的正确形式填空。

    Sara and her father planned ____ trip to a mountain near their home. The path they chose____ (begin) at the foot of the mountain and led all the way ____ the top. Sara packed lunches earlier that morning. ____ (she) father filled their backpacks with other things and they  ____ (be) off!

    As they started up the path, Sara’s father pointed out many different____ (plant) that grew on the path. He showed Sara the ____ (different) between the____ (leaf) of trees.  Sara was glad ____ her father knew so much! She always learnt something whenever they went on a trip. This time, she was sure that she ____ learn more.

既是中国近代第一批被迫开放的通商口岸，又是改革开放时期的经济特区的是（　　）

与999相邻的两个数是（  ）

页岩气是蕴藏于页岩层可供开采的天然气资源。我国页岩气资源潜力大，初步估计与常规天然气相当。下图示意页岩气开采过程，其核心技术是水平井技术与水力压裂技术。读图，常规天然气储存的地质构造是（   ）