2.He claimed to have seen a round black creature moving quickly through the water.

他声称看见一个黑黑的、圆圆的动物在水中快速游动。 to have done 是不定式的完成式，表示该不定式动作发生在谓语动词之前。 Tom claimed to_have_seen an alien, but no one believed him.

汤姆声称见过外星人，但是没人相信他。 3.There have been reports of monsters in Lake Tianchi since the beginning of the last century, although no one has seen one close up.

自上世纪以来，一直就有关于天池怪物的报道，尽管还不曾有人近距离目睹过。 there be句型的现在完成时，强调过去状态对现在造成的影响。 There_has_been below average rainfall this month.

这个月的降雨低于平均降雨量。 　　

　　1．(教材51)It often gets angry and will attack anyone who goes close to it.

　　它常变得很生气并会攻击靠近它的人。

　　attack v．攻击，进攻n.袭击，侵袭，攻击， (疾病等的)侵害，损害

　　(1)attack sb. with sth.　　　 用某物攻击某人

　　be attacked with ... 患(病)，得(病)

　　(2)make an attack on/upon 攻击，向......进攻

　　be/come under attack 遭到......的攻击/抨击

　　a heart attack 心脏病突发

　　①When he was walking home from the office that night, he was attacked by several robbers.

　　那天晚上他从办公室往家走的时候，被几个强盗袭击了。

　　②His grandmother's sudden death of a heart attack drove Eric to study medicine.

　　艾利克的奶奶突发心脏病去世，这促使他学医。

　　③The general commanded that the soldiers (should) make an attack on/upon the enemy.

　　将军命令士兵对敌人发起进攻。

　　④The company came under_attack for the firing of 50 employees.

那家公司因解雇50名员工而遭到抨击。