________ the difficult maths problem, I have consulted Professor Russell several times.

A. Working out          B. Worked out

C. To work out            D. Work out

The lecture ________, a lively question-and-answer session followed.

A. being given         B. having given

C. to be given          D. having been given

For those with family members far away, the personal computer and the phone are important in staying________.

A. connected           B. connecting

C. to connect          D. to be connected

— I hope to take the computer course.

— Good idea. ____ more about it, visit this website.

A. To find out             B. Finding out

C. To be finding out       D. Having found out

He is thought ___foolishly .Now he has no one but himself to blame for losing the job.

A. to act              B.  to have acted

C.   acting            D. having acted

When it comes to __ in public, no one can match him.

A.  speak               B.  speaking

C. being spoken         D. be spoken

There is a note pinned to the door______ when the shop will open again.

A. saying           B. says

C. said             D. having said

Clearly and thoughtfully________, the book inspires confidence in students who wish to seek their own answers.

A. writing                B. to write

C. written                D. being written

Last night, there were millions of people _______ the opening ceremony live on TV.

A.watch               B. to watch

C. watched             D. watching

There are still many problems ______ before we are ready for a long stay on the Moon.

A. solving               B. solved

C. being solved          D.to be solved