【正文】
when you go to see the doctor ________ you have to wait. A. even if B. in case C. as if D. in order that 5. ________ how mirrors produce images, we need to know what light does. A. Understanding B. Understood C. To understand D. Having understood 6. Steps must be taken ________ this kind of disaster will never happen again. A. because B. even if C. so that D. as 7. Today, we will begin ________ we stopped yesterday so that no point will be left out. A. when B. where C. how D. what 8. Only when the final examination was ing ______ he had quite a lot to do. A. he realized B. he had realized C. did he realize D. had he realized 9. When ________, the museum will be open to the public next year. A. pleted B. pleting C. being pleted D. to be pleted 10. Nancy enjoyed herself so much ________ she visited her friends in Sydney last year. A. that B. which C. when D. where 11. The engineers are so busy that they have zero time for outdoor sports activities, ________they have the interest. A. wherever B. whenever C. even i