() 25. I don't need to call Dick up I'll see him soon.

   A. when   B. though

   C. until   D. because

() 24. Put on more clothes, you may catch a cold.

   A. and   B. but

   C. or   D. though

() 23. He waited the volcano became quiet and he was able to return two days later.

   A. when   B. before

   C. as   D. until

() 22. She worked hard she could pass the exam.

   A. since   B. so that

   C. as if   D. unless

() 21. he studies hard,he will never pass the examination.

   A. If   B. Unless

   C. Even if   D. Even though

() 20. He is very kind he looks serious.

   A. because   B. though

   C. if   D. when

() 19. you understand this rule,you'll have no further difficulty.

   A. Once   B. Unless   C. As   D. Until

() 18. the man grew older,he lost interest in everything except gardening.

   A. With   B. Since   C. While   D. As

() 17. You may borrow this book— you promise to give it back.

   A. in case   B. so long as

   C. as if   D. even if

() 16. I have been keeping that photo I can see it every day.

   A. which   B. where   C. whether   D. when