I don't know when the bridge was built_______，but it must be very old．（ ）
A．exactlyB．carefullyC．luckilyD．easily
Yesterday our headmaster made a speech ______ environmental protection， and we learned something about recycling of waste．（ ）
A．onB．atC．to
Keep trying， ______ you might surprisingly find hidden abilities within you．（ ）
A．butB．andC．or
_______ fun it is to have a field trip on the Orange Island!（ ）
A．WhatB．What aC．How
You don't look well． What's the matter with you？
_____． （ ）
A．I won the gameB．Maybe I have a fever
C．That's too bad
I'll never forget the story_____．（ ）
A．that cheers me upB．who cheers me up
C．what cheers me up