This is partly because isolating the oligomers is both costly and time-consuming - processing hundreds of kilograms of dried plant material often yields only a few milligrams of a single product.
2
最后是那些为数甚多、通常低于海平面的火山，它们在板块分离、新壳产生的延展脊状突起上形成。
Finally there are those-a great many, but normally deep under the ocean-formed at the spreading ridges where tectonic plates pull away from each other and new crust is formed.
3
忆归期，数归期，梦见虽多相遇稀，何日重逢，不再分离？坛。
Thee number of return, return, although the dream encounter thin, when again, no longer separated?
点击反馈