有only when necessary和if necessary吗?有什么区别吗?

有only when necessary和if necessary吗?有什么区别吗? if only ,if necessary when it is necessary 为什么可以变为when necessary? To be taken when necessary. 这句该怎么翻才更通顺?英语谢绝软件翻译.For use only when actually necessary; take the indications of crop and soil analyses into consideration. 英语翻译Mass production methods can only be employed when the market is large enough to justify the enormous but necessary start up costs. if it is necessary /if necessary /when it is necessary 意思一样吗 only when the only是什么意思 She will help you when it necessary怎样改是改错,里面有一个单词用错了 Canals()the river water to the fields when necessary为什么填carry 而不是bring 请问有什么区别 请问only when 和 only then 用法上有什么区别? necessary it only hurts when i breathe谁有Sarah Connor 《 It only hurts when i breathe》的歌词. 关于一道英语语法technologies make global exploitation of nature not only possibly, but seemingly necessary. 我认为应该把possibly改为possible 答案说是吧necessary改为necessarily 为什么呢 不是有这样的句子 比方说 I be necessary for和be necessary to 有何区别 international marketing难题“Critically evaluate the extent to which it is possible,necessary or even desirable to attempt to standardise the marketing mix when moving from one international environment to another.”You should consider only one o 一句英语翻译中的疑问：While violence is rarely justifiable as a means of questioning authority, peaceful challenges to political and legal authority, by many people, are not only justifiable but actually necessary when it comes to enhancin It is necessary ( ) travellers to take a map when