按所给的汉语，用英语完成下列句子。
1. 我表妹告诉我这把吉他她买了不到三个月。
My cousin told me _______________________________________________________.
2. 大家都知道火星上的重力只有地球重力的约八分之三。
It's known to all that the gravity on Mars _________________________________ on Earth.
3. 教练告诫队员要把全部的精力投入到足球训练中去。
The coach asked the players _____________________________________ football training.
4. 他们别无选择，只得接受我们的建议。
They had ________________________________ our advice.
5. 恐怕你们做的事情已经损害了我们的环境了。
I'm afraid what you did _____________________________________________________.
6. 尽我们的最大努力处理好每一个教育上的挑战是我们的职责所在。
It's our duty ______________________ the challenge in education.
1. she had had the guitar for less than three months
2. is only about three-eighths of that
3. to put all their effort into
4. no choice but to take/accept
5. has done harm to our environment
6. to try our best to deal with