纠结的一题阅读！！！不好理解啊

Paragraph2: Mineral deficiencies can often be detected by specific symptoms such as chlorosis (loss of chlorophyll resulting in yellow or white leaf issue), necrosis (isolated dead patches), anthocyanin formation (development of deep red pigmentation of leaves or stem), stunted growth, and development of woody tissue in an herbaceous plant. Soils are most commonly deficient in nitrogen and phosphorus. Nitrogen-deficient plants exhibit many of the symptoms just described. Leaves develop chlorosis; stems are short and slender, and anthocyanin discoloration occurs on stems, petioles, and lower leaf surfaces. Phosphorus-deficient plants are often stunted, with leaves turning a characteristic dark green, often with the accumulation of anthocyanin. Typically, older leaves are affected first as the phosphorus is mobilized to young growing tissue. Iron deficiency is characterized by chlorosis between veins in young leaves.

¡deep red discoloration between the veins.

¡white or yellow tissue between the veins.

¡dead spots between the veins.

¡characteristic dark green veins.

答案是2怎么理解呢，求助各位大侠！！

我觉得是这样的，抓住两句重点Iron deficiency is characterized by chlorosis between veins in young leaves.和Mineral deficiencies can often be detected by specific symptoms such as chlorosis (loss of chlorophyll resulting in yellow or white leaf issue),

而问题是a symptom of iron deficiency is the presence in young leaves of铁质缺乏的表现是什么？上边讲铁质缺乏的表现是在young leaves的veins,而金属物质的缺乏可以被探测出来通过specific symptoms such as chlorosis，而chlorosis的缺乏可以导致yellow or white leaf issue.

white or yellow tissue between the veins我理解的意思是树叶纹理之间is white or yellow.正好对应了yellow or white leaf issue.叶子的颜色是yellow or white.

不好意思，这是我的一点浅显的理解，不知道对不对。

再看看这一题

Paragraph2: Speculation on the origin of these Pacific islanders began as soon as outsiders encountered them, in the absence of solid linguistic, archaeological, and biological data, many fanciful and mutually
                    exclusive theories were devised. Pacific islanders ere variously thought to have come from North America, South America, Egypt, Israel, and India, as well as Southeast Asia. Many older theories implicitly deprecated the navigational abilities and overall cultural creativity of the Pacific islanders. For example, British anthropologists G. Elliot Smith and W. J. Perry assumed that only Egyptians would have been skilled enough to navigate and colonize the Pacific. They inferred that the Egyptians even crossed the Pacific to found the great civilizations of the New World (North and South America). In1947 Norwegian adventurer Thor Heyerdahl drifted on a balsa-log raft westward with the winds and currents across the Pacific from South America to prove his theory that Pacific islanders were Native Americans (also called American Indians). Later Heyerdahl suggested that the Pacific was peopled by three migrations: by Native Americans from the Pacific Northwest of North America drifting to Hawaii, by Peruvians drifting to Easter Island, and by Melanesians. In 1969 he crossed the Atlantic in an Egyptian style reed boat to prove Egyptian influences in the Americas. Contrary to these theorists, the overwhelming evidence of physical anthropology, linguistics, and archaeology shows that the Pacific islanders came from Southeast Asia and were skilled enough as navigators to sail against the prevailing winds and currents.

¡Egyptians were known to have founded other great civilizations.

¡Sailors from other parts of the world were believed to lack the skills needed to travel across the ocean.

¡Linguistic, archaeological, and biological data connected the islands to Egypt.

¡Egyptian accounts claimed responsibility for colonizing the Pacific as well as the Americas.

答案是选2，但是文中说是skilled enough to navigate，   答案里是lack the skills .这又怎么理解呢？还是答案是错的！！

这道题在这句上Many older theories implicitly deprecated the navigational abilities and overall cultural creativity of the Pacific islanders. For example, British anthropologists G. Elliot Smith and W. J. Perry assumed that only Egyptians would have been skilled enough to navigate and colonize the Pacific.

Many older theories 就是early researcher to believe所以就定位上面一句

Sailors from other parts of the world were believed to lack the skills needed to travel across the ocean.你要看见这个选项里有一个from other parts 也就是说除了EGYPT以外没有其他人有能力去穿越海洋所以你就知道选哪个了

我要回学校了，上不了网了，回来再联系

看懂了！！！谢谢啊！！！自己还是词汇薄弱啊~~