(A) Generally, Europe and Asia (B) are regarded as being distinct continents, but they are simply (C) vast geography divisions of the larger lad mass (D) known as Eurasia.

An ambitious person (A) is committed to (B) improve his or her (C) status (D) at work.

(A) Once you have finished an article and (B) identified its main ideas, it may not (C) be necessary to reread it (D) again.

The substance is very toxic. Protective clothing must be worn at all times.

     A. Since the substance is very toxic, so protective clothing must be worn at all times.

     B. So toxic is the substance that protective clothing must be worn at all times.

     C. The substance is such toxic that protective clothing must be worn at all times.

     D. The substance is too toxic to wear protective clothing at all times.

The government knows the extent of the problem. The government needs to take action soon.

     A. The government knows the extent of the problem whereas it needs to take action soon.

     B. The government knows the extent of the problem so that it needs to take action soon.

     C. Knowing the extent of the problem, the government needs to take action soon.

     D. The government knows the extent of the problem, or else it needs to take action soon.

Charles would have won the essay contest if he had typed his paper.

     A. Charles won the essay contest in spite of not typing his paper.

     B. Charles did not win the essay contest because he did not type his paper.

     C. Typing his paper made Charles win the essay contest.

     D. Charles did not win the essay contest even though he typed his paper.