To be put out by hitting a ground ball that is fielded and thrown to first base.
打滚地球出局：因打出的滚地球被截或被掷回一垒而出局
existing (or not existing) in large numbers or amounts
为数众多（或为数不多）
new textbooks on particle physics are thin on the ground.
粒子物理学的新教材为数不多。
do preparatory digging or other work prior to building or planting something
翻土，犁地；破土，动工
another term for break new ground below
同后面 break new ground
do something innovative which is considered an advance or positive benefit
开辟新天地，创新
do something which leaves someone without a reason or justification for their actions or opinions
使（某人的）行为无正当理由，使（某人的）观点无据可依
become more popular or accepted
越来越得人心，越来越为人们所接受
new moral attitudes are gaining ground.
新的道德观越来越为人们所接受。
get closer to someone or something one is pursuing or with whom one is competing
逼近（追赶对象，竞争对手），追上
the dollar gained ground on all other major currencies.
美元已赶上所有其他主要货币。
(informal)become part of an enterprise in its early stages
(非正式)在企业的草创阶段加入
start or cause to start happening or functioning successfully
（使）顺利开始；（使）起作用
he doesn't appreciate the steps he must take to get the negotiations off the ground.
他不喜欢自己为使谈判得以开始而不得不采取的那些步骤。
retreat or lose one's advantage during a conflict or competition
让步；退却；失去优势
he refused to give ground on this issue.
他拒绝在这一问题上让步。
(of a fox or other animal) enter its earth or burrow
（狐狸等）钻入地穴
not retreat or lose one's advantage during a conflict or competition
不让步；不退却；保持优势
you will be able to hold your ground and resist the enemy's attack.
你将能够坚守阵地并抵御敌人的进攻。
get closer to someone ahead in a race or competition
追近，赶上
in a place where real, practical work is done
在现场，在实地
the troops on the ground are cynical.
战地的部队只顾自身的安危。