________ different kinds of pianos, they are sure they can satisfy people's needs．

A．To produce

B．Being produced

C．Produced

D．Having produced

Success always comes after many ________, in other words, ________ is the mother of success．

A．failures; failure

B．failure ;a failure

C．failure; failure

D．failures; a failure

Tyron was very angry, but cool-headed enough to ________ rushing into the boss's office．

A．prevent

B．avoid

C．protect

D．allow

He has been training for a long time, so he is ________ to succeed at his first ________．

A．possible; attempt

B．probable; try

C．likely; attempt

D．perhaps; try

________ days went by, he didn't succeed in anything he had planned．

A．With

B．When

C．As

D．While

She felt ________ about her future．

A．puzzle

B．puzzling

C．puzzled

D．puzzles

“We can't go out in this weather, ” said Bob,________ out of the window．

A．looking

B．to look

C．looked

D．having looked

Listen! Do you hear someone ________ for help?

A．call

B．calling

C．to call

D．called

Li Ming speaks English very well ________ he were an English boy．

A．so that

B．even if

C．now that

D．as though

I can make you ________ what I say, but you can't make yourself ________ in English．

A．understand; understand

B．understand; understood

C．to understand; understand

D．understand; to be understood