岂不 + 是 + Consequence + 了/吗
The adverb 岂不 (qǐbù) is used in rhetorical questions to mean "wouldn't that be" or "isn't that," implying an obvious or undesirable consequence. It is a literary and emphatic expression that expects the listener to agree with the implied conclusion. For example, 那岂不是太浪费了 means "wouldn't that be too wasteful?"
这么好的机会不抓住,岂不太可惜了?
zhème hǎo de jīhuì bù zhuāzhù, qǐ bú tài kěxī le?
Wouldn't it be such a shame not to seize such a great opportunity?
大家都去了你不去,岂不让人觉得奇怪?
dàjiā dōu qù le nǐ bú qù, qǐ bú ràng rén juéde qíguài?
Everyone else is going but you're not — wouldn't that seem strange?
花了这么多时间准备,现在放弃岂不前功尽弃?
huāle zhème duō shíjiān zhǔnbèi, xiànzài fàngqì qǐ bú qiángōngjìnqì?
After spending so much time preparing, wouldn't giving up now mean all that effort was wasted?