6. obstacle n. 障碍(物);妨碍
例句：Her parents' opposition is an obstacle to her marriage.
她父母的反对是她结婚的障碍。
7. exert vt.用(力); 尽(力)；运用, 发挥, 施加
例句：He's been exerting his influence on his friend to change his decision.
他一直在影响他的朋友改变决定。
8. hinder vt. 阻碍,妨碍,阻挡
例句：Heavy snow hindered construction work.
大雪阻碍了建筑工程的进展。
9. witness vt. 是发生…的地点（或时间、组织等）；见证
例句：The year 1849 witnessed a great war in Hungary.
一八四九年匈牙利发生了一场大战。
10. channel n. 途径;渠道;手段
例句：You should go through the official channels if you want the government to help.
你应该通过正式渠道来争取政府的帮助。