Books have always been the main tools for teaching.
But a vast number of new tools have come to use in this 【S1】______
century. Take audiovisual aids for an example. "Audiovisual" 【S2】______
means "hearing-and-seeing". These aids to learn include 【S3】______
films, television, audiotapes, videotapes, slides, recordings,
charts, or graphs. In many schools there are language 【S4】______
laboratories where students studying foreign languages can
listen to recordings of natural speakers. The students can 【S5】______
record their speech and play back tape to hear their 【S6】______
own pronunciation. Tremendous strides have been made
in television instruction. Thousands of schools are now
using television as part of the irregular teaching program. 【S7】______
Hundreds of closed-circuit television systems have been
set in schools and colleges. There are more than 200 【S8】______
educational television stations in the United States
majoring in programs of many types. For such large 【S9】______
audiences, television stations can spend more money
to preparing programs than any one school could spend. 【S10】______
In television classrooms, students may see expensive
scientific equipment in use. They may see close-ups of
historical documents. Or they may hear talks by famous
scientists or writers.
【S1】