Official 22 Lec 2
Question 1 of 6
What is the main purpose of the lecture?

A.

To compare solutions to the greenhouse-gas problem

B.

To examine methods used to study star formation in other solar systems

C.

To discuss evidence for liquid water on young Earth and Mars

D.

To discuss attempts to solve a puzzle related to the Sun

正确答案:D

显示答案
进入答题
00:00
00:00
隐藏原文

译文

精听文本