雅思寫作話題及范文:The diagrams below show the life cycle of a species o.

雅思寫作話題及范文:The diagrams below show the life cycle of a species o.

范文

Salmon begin life as eggs on a pebbly riverbed, hidden among reeds in the slow-moving upper reaches of a river. After five to six months the eggs hatch into ‘fry’. For approximately the next four years, these baby salmon will live in the lower, faster-flowing waters of their river. During this time they measure between three and eight centimetres in length.

By the time salmon reach twelve to fifteen centimetres, they are termed ‘smolt’, and at this time they migrate further downriver into the open sea. After five years at sea, the salmon will have grown to adult size, which is between seventy and seventy-six centimetres. They then begin swimming back to their birthplace, where they will lay their eggs, and the cycle starts anew.

In summary, the salmon passes through three distinct physical stages as it grows to maturity.Each of these stages takes place in a very different aquatic location. It is noteworthy that the first two stages of this fish’s life occur in a fresh water environment, while the third stage is lived in saltwater.

鮭魚的生命起源于卵石河床上的卵，隱藏在緩慢移動的河流上游的蘆葦中。五到六個月后，雞蛋孵化成“魚苗”。大約在接下來的四年里，這些小鮭魚將生活在河流中流速更快的較低水域。在此期間，它們的長度在3到8厘米之間。

當鮭魚長到12到15厘米時，它們被稱為“斯莫爾特”，此時它們會進一步向下游遷徙到公海中。在海上生活五年后，鮭魚將長成成年魚，大小在70到76厘米之間。然后，它們開始游回它們的出生地，在那里產(chǎn)卵，然后循環(huán)又開始了。

綜上所述，鮭魚在生長成熟的過程中會經(jīng)歷三個不同的生理階段。每個階段都發(fā)生在非常不同的水生位置。值得注意的是，這種魚的前兩個階段生活在淡水環(huán)境中，而第三個階段生活在鹽水中。

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