Kofi Annan says helping survivors of last week’’s earthquake and (1)________in the Indian Ocean is (2)________. The United Nations secretary-general says countries that have offered aid must (3)________and provide it. The offers add up to around (4)________dollars. United Nations officials say (5) ________of that is needed during the next six months.The concern about offers of international aid is (6)________. For example, the earthquake in Bam, Iran, in (7)________of 2003 killed more than (8) ________people. Countries and groups offered hundreds of millions of dollars (9) ________. The United Nations says it has (10)________only about (11)________dollars in aid received so far. Governments and organizations that offered help (12) ________that, however.On (13)________Mr. Annan met with world leaders in Jakarta, Indonesia to discuss aid for (14)________. The leaders discussed and (15)________the idea of (16)________owed by affected nations. But the leaders did not say they would do so. Some said that (17)________to survivors would be more helpful.Representatives of (18)________countries and international organizations attended the meeting in Jakarta. Officials say they will cooperate to develop (19)________ for the Indian Ocean and the (20)________.

十字丝玻璃片上的上、下短丝是测距离用的，称为（）。

A.视距丝

B.上丝

C.下丝

D.视距