Vous avez cherché: if and only if (Anglais - Chinois (simplifié))

if and only if
当且仅当

only if
只要不是

once and only
唯一一次

the one and only
别无分号

the one and only way
不二法门

5.2 an intangible asset should be recognized if, and only if:
5.2 在并且只在下列情形下，才应该认列无形资产：

only if given away early on
除非早点送人

(only if significant to economy)
对外贸易 - 服务(仅当对经济比较重要时)

“(4) the presumptions in paragraph (3) shall apply if, and only if
"(4) 在下述情形下而且只有在下述情形下，应适用第(3)款中的推定：

(output indicators only if available).
（产出指标，如果有的话）。

only individuals can hate and only individuals can dialogue.
只有个人,才会产生仇恨,只有个人,才能进行对话。

11.9 an enterprise should offset current tax assets and current tax liabilities if, and only if, the enterprise:
11.9 企业冲消流动税款资产和流动税款负债的条件，而且是唯一条件如下；

but this will be possible if, and only if, the parties to the conflict live up to their responsibilities to enable and facilitate access.
但是，只有冲突各方履行其允许并便利进入的责任，这才是可能的，除此之外绝无可能。

and only if a treaty is drafted against this background will it enjoy wide support and be properly implemented.
因此，只有在这种背景下拟定的条约，才能取得广泛的支持并得到妥善执行。

i am confident that we will prevail on that journey, but only if we are not complacent or passive and only if we support and defend our deeply held values.
我相信，我们定会在这一征程中占据上风，但是唯一的条件是，我们不固步自封或采取消极态度，同时，我们支持和捍卫我们根深蒂固的价值观。

(3) to be completed for movements within the oecd area and only if b(ii) applies.
(3) 如果b(ii)项在此适用，应针对经合组织所属地区内的越境转移予以填写。

sanctions should be renewed only if they were effective and only in the event of non-compliance by the target state.
只有当制裁奏效，而且只有在目标国家违约的情况下，才应延长制裁期限。

if -- and only if -- the parties do not undertake credible inquiries within six months, the report recommends pursuing accountability through international judicial action.
报告建议，如果且只有如果双方未在6个月内开展可信调查，将通过国际司法行动来追究当事人的责任。

the judges of the pretrial chamber shall serve only if and when their services are needed.
预审法庭法官仅在需要其服务时履行职务。

2. at h duty stations, mobility is paid upon fourth assignment and only if staff member had at least two previous assignments at a to e duty stations
2. 在h类工作地点，第四次派任、并且以前至少两次派到a类至e类工作地点的工作人员可得到调动津贴