Light fittings with metal parts should always be earthed.有金属部件的照明装置都应该走地线。It is desirable that compensating cables be run in earthed conduit.补偿导线最好在地下管道中穿过.He carefully earthed up the roots of the newly - planted tree.他仔...
在保单有效期内,所缴纳的保险费是有保障的。Premiums are guaranteed throughout the term of the policy.本协议的有效期已过。The period of validity of the agreement has expired.这份保证书有效期为一年.This guarantee is valid for one year....