Good luck !

I.1 hoa worked hard-c so she passed her exam

2 lan is sick today-b so she won't go to school

3 hoai woke up late-a so she didn' have time for breakfast

4 it was hot-d I returned on the air conditioner

II.1 nam went on excursion to oxford last sunday

2 he went there by bus

3 he met some english students in the bookshop

4 he practiced speaking english with many foreigners

5 in the afternoon he bought a dictionary and a book " oxford university" 

6 yes he did

III.1 from

2 on

3 to

4 by

IV.1 I wish I had an Iphone

2 she wanted to go home because she was tired

3 the examiner asked lan if she spoke english