1．She failed this English examination again. This is because she sometimes has trouble (pay) attention to her study.
paying 解析：句意：她这次英语考试又一次没及格。这是因为她有时很难将注意力集中在她的学习上。have trouble (in) doing sth.为固定结构，意为：做某事有困难。
2．To his surprise, Jack found his son (dress) as Santa Claus on Christmas Eve.
dressed 解析：句意：使杰克惊讶的是，他发现儿子在圣诞节前夜被装扮成了圣诞老人。此处为“find＋宾语＋宾语补足语”结构，用过去分词作宾语补足语。dress意为“给(某人)穿衣”，常用于dress sb.或sb.be/get dressed结构。
3． (compare)with the traditional trade mode, they don’t have to spend money in renting a house.However, there are still some disadvantages to online shopping.
Compared 解析：句意：与传统的商业模式相比，他们不需要花很多钱去租房子。但是，网购仍然有一些劣势。compared with为独立成分，在句中作状语。
4．Another student, a 15yearold girl from Guangdong, was afraid of exams. She would get very upset with the exam paper (lie) in front of her.
lying 解析：考查with＋宾语＋宾补。此处宾语与宾补之间是主动关系，应该用v.ing形式。
5．Failing (turn) in your homework on time will directly affect your grade for a certain course.
to turn 解析：句意：不按时交作业会直接影响你某门课程的成绩。fail to do 不能做……；未能做……。
