（ ）是细胞进行代谢的内部环境，其主要成分是水及各种无机盐。

(单选题)—What do you do?—______ (单选题)Your brother is ______ to go to school. (单选题)______ a cold winter morning he left ______ Shanghai. (单选题)______ foreigners come to our country every year. (单选题)______ playground is much larger than ______. (单选题)I have ______ to tell you. (单选题)Mrs. White is ______ in the park now. (单选题)There is ______ water here, and there are quite ______ empty (单选题)There are many ______ teachers in my school. (单选题)—This is Andy speaking. ______—This is Tim.