In the following passage some of the words have been left out. Read the passage carefully and select the correct answer for the given blank out of the four alternatives.

The ................ of lectures should be enhanced by introducing the lecture with a brief review of the work..........., it should also be indicated how the day's lecture............ into the course pattern. A lecture should .............be presented in one unbroken discourse. Unless exceptionally interesting, a long lecture strains the ..........of a concentrated listening, causing intermittent wandering of attention and loss of continuity in thought.

The ................ of lectures should be enhanced by introducing

• condition

• effectiveness

• efficiency

• interest