One day Chuck is on a flight （）the Pacific Ocean suddenly （）his plane crashed.

单项选择题—It was very crowded （）I went there last night. —I don't care whether it's crowded or not. I'd like to see it anyway.

A. though
B. because
C. when
D. since

单项选择题Friendship helps us understand （）we are, （）we need each other and （）we can do for each other.

A. what when that
B. who why what
C. where why that
D. who when how much

单项选择题Many people keep dogs as pets because dogs are regarded as（）friends to people.

A.lonely 
B.only 
C.loyal 
D.fair

单项选择题—The research on the new bird flu virus vaccine is challenging and demanding. Who do you think can do the job — （）my students have a try

A. Shall
B. Must
C. Will
D. May

单项选择题—What was your impression of last night's lecture —Speaking（）, I thought it was rather boring.

A. very
B. honest
C. really
D. honestly