mantle piece

同根派生

However, it seemed better for nucleated pearl production to clean the mantle piece with sterilized sponge block or absorbent tampon than washing according to the appearance data.
這些差異，從統(tǒng)計(jì)學(xué)角度看沒(méi)有明顯區(qū)別，但從表觀數(shù)據(jù)可見(jiàn)，無(wú)論是成珠率還是優(yōu)珠率，育珠細(xì)胞小片用海緜塊擦和脫脂棉球擦比不擦明顯要高，表明小片不擦不利於有核珍珠的培育。
He bit off a large piece of the apple.
他咬下一大塊蘋(píng)果。
I need a piece of string to tie this parcel up.
我需要一根細(xì)繩把這包裹紥起來(lái)。
The earth has a core and a mantle around it.
地球的中心是地核，地核的周圍是地幔。
The mountain was covered with a mantle of snow.
山上覆蓋著一層雪。