68. 老师和你谈话时,背对着老师在某种程度上会使你自在,但那是不礼貌的。
When a teacher is talking to you, ________ ________ _______ _______ him/her may make you feel _______ _______to some degree, but it is impolite to do so.
69. 接近目的地了,疲惫的孩子们又活跃起来了。
The tiring children ________ ________ _______ again when they________ ________ _______their destination.
70. 为了使土壤免受疾病的影响,专家继续他们的实验。
To ________the soil _______ ________ disease, the experts ________ ________ ________ their experiment.