社会主义道德原则的核心是（ ）。

(单选题)According to Para.2, the atmosphere on Mars would ______. (单选题)The author discusses environments (Line2) in Para. 2 in orde (单选题)According to Para l, which of the following is true of space (单选题)What can be learned from Dr. Kaminski? (单选题)What is most likely to work on dogs’ communicative ability d (单选题)The underlined word “dropped” (Line5, Para7) means “______ ” (单选题)What is the key information the author wants to say in Para. (单选题)For which of the following reasons will Door2Door be able to (单选题)What is the purpose of the letter? (单选题)What kind of business is being advertised?