A lack of
缺乏，缺少
🧩 词语组成解析
lack
[læk]
vt. 缺乏，缺少;需要的东西;
n. 缺乏，不足，没有;缺少的东西;
of
[əv]
prep. 关于;属于…的;由…制成;
aux. 助动词 [非标准用语、方言] =have [主用于虚拟语气];
🗣️ 情景例句
Just a little off all over off the sides.
两边都稍微短一点
You must have dialed the wrong number.
你肯定拨错了号。
Then knowledge began to be accumulated according to a systematic plan.
于是，知识便开始有系统有计划地积累起来。