Since 1965, when is equipment became operational, a device called Eros has been helped to make sky traffic__1__ safe. Eros is short for Eliminate Range Zero Systemrange zero meaning collision. Basically Eros is a computer system measures, with great speed and precision, closing__2__ speed （ the speed at which two objects are approaching each other ） and range （ the distance apart of the objects ）.Eros can warn aircraft approachable each other at jet__3__ speeds and can provide protection for as many as a thousand aircraft in wide area. The pilot of an Eros?equipped aircraft heading for a collision hear a warning noise in his ear?phones__4_when his airborne computer calculates that he is within thirty seconds or half a mile （ whichever occurs first ） of other aircraft.__5__ At the same time, a flashing red arrow on the device's indicator panel instructs him to climb. Simultaneously, in the other aircraft, __6__ the signal is automatically reversed: the flashing arrow tells the pilot to climb. The newer Eros II system can accommodate a total of two thousands aircraft at one time within a 140?mile radius__7__ Every three seconds, each Eros?equipped plane automatically reports to ground stations and to similarly equipped aircraft their precise range, altitude and approach rate. The producers__8__ of Eros, the McDonnell Dougals Corporation in the U.S., are now studying the fitting of Eros and will do more to make__9__ the sky safer: they shall also lighten the work of air?traffic__10__ controllers and increase the efficiency of airports.
【答案】
1. helped—helping.現(xiàn)在完成進(jìn)行時(shí)
2. measures前加that/which.that/which引導(dǎo)定語(yǔ)從句，修飾先行詞a computer system
3. approachable—approaching.approaching為現(xiàn)在分詞，修飾aircraft，相當(dāng)于that/which are approaching each other
4.hear—hears.其主語(yǔ)是the polit
5. other—another.相對(duì)于上提到的an Eros?equipped aircraft， 此處為另一架飛機(jī)
6. climb—descend.根據(jù)上下文的意義，考試大一架飛機(jī)下降，另一架飛機(jī)上升，以免相撞
7.thousands—thousand.根據(jù)語(yǔ)法規(guī)則，數(shù)詞hundred 、thousand 、million等詞一般為單數(shù)形式
8. their—its.指上文中的主語(yǔ)each equipped plane
9. 去掉make前的to.do與make并列作動(dòng)詞謂語(yǔ)
10. shall—will.表示一般將來，shall常用于考試大第一人稱，will則常用于第二和第三人稱