重点讲解：
1. in an effort to do sth.
努力，试图做某事；
eg. She has been studying very hard in an effort to catch up with her classmates.
她学得非常努力，以便赶上她的同学。
eg. They attacked furiously in an effort to score a tying goal.
他们猛烈进攻，企图得一分以打成平局。
2. be oblivious to/of sth.
不知道的；未注意的；未觉察的；
eg. She lay motionless where she was, oblivious to pain.
她一动不动地躺在原地，已经感觉不到疼痛。
eg. Llewelyn appeared oblivious of his surroundings.
卢埃林看起来没有注意到他周围的情况。
3. in sb.'s presence
当着…的面；在…面前；
eg. Try not to allude to this matter in his presence because it annoys him to hear of it.
他在的时候千万别提及这件事，他听了要生气的。
eg. Don't say anything about anyone in their absence that you would not say in their presence.
不要在背后说那些你不会在别人面前说的话。