Artificial intelligent assistant

plumb-line

plumb-line
n line with a plumb(1) attached to one end 铅垂线.

牛津英汉双解词典

edrTRBnvbvbfdvEzudIdQg1m88q5imAx0fJs98kZOqu6gcmlb31bzg dec68abdc47ba08c812227a3533f9403