Modern zoos are very different from zoosthat were built fifty years ago. At that time， zoos were places 21 people could goto see animals from many parts of the world. The animals lived incages that were made 22 concrete withiron bars， cages that were easy to keep clean.
【例】If the test taker answers _____， the next item will be more difficult. If he or she answers incorrectly， the next question will be easier.
如书写和形态变化线索、词汇线索、句法线索、社会文化线索，并根据有关的线索进行猜测，作出合理的判断。如:And the clerk confirmed that his plane was leaving at nine o’clock three days from that day…
