adv. 一次,一趟;一倍;曾經(jīng);一旦;
conj. 一旦…就…;一經(jīng);
n. 一次,一回;
?? on=one一+ce次 → 一次
"Once in the bloodstream, the bacteria adhere to the surface of the red cells."
細菌一進入血液里,就附著在紅細胞表面上。
近義:heretofore, occasionally, onetime, previously, sometimes, thereinbefore
a. 感激的;有責(zé)任的;必須的
近義:indispensable, astricted, necessary, needful, obligated, obligatory
反義:intentional, premeditated, purposive, spontaneous, wilful, willful