中学阶段友谊的主要特征有()、亲密性和矛盾性。
参考答案:稳定性
We on it for several hours but we haven't yet reached any conclusion.
A.are working
B.work
C.have been worked
D.have been working
超前地质预报实施工过程中应积极识别各种(),保障人员和机械设备安全。