Never before ______ in greater need of modern public transport than it is today.

A. has this city been       B. this city has been   C. was this city        D. this city was

 ______ in the regulations that you should not tell other people the password of your e-mail account.

A. What is required     B. What requires        C. It is required       D. It requires

 At last, we found ourselves in a pleasant park with trees providing shade and ______ down to eat our picnic lunch.

A. sitting              B. having sat           C. to sit               D. sat

 More and more people are signing up for Yoga classes nowadays, ______ advantage of the health and relaxation benefits.

A. taking               B. taken                C. having taken     D. having been taken

 It was unbelievable that the fans waited outside the gym for three hours just ______ a look at the sports stars.

A. had                  B. having               C. to have          D. have

 He transplanted the little tree to the garden ______ it was the best time for it.

A. where                B. when             C. that             D. until

 ______ into use in April 2000, the hotline was meant for residents reporting water and heating supply breakdowns.

A. Put                  B. Putting          C. Having put           D. Being put

 He got well-prepared for the job interview, for he couldn’t risk _______ the good opportunity.

A. to lose              B. losing               C. to be lost           D. being lost

 Professor Smith, along with his assistants, ______ on the project day and night to meet the deadline.

A. work                 B. working          C. is working           D. are working

 More than a dozen students in that school ______ abroad to study medicine last year.

A. sent                 B. were sent            C. had sent         D. had been sent