You can remember the meaning of 大不了 with this easy mnemonic:
The <strong>biggest</strong> (大) news of the month is Dalai Lama will come and deliver a speech. The local authorities are concerned whether or <strong>not</strong> (不) they have the <strong>complete</strong> (了) crowd-control and terrorist-prevention manpower. <strong>At worst</strong>, the Dalai Lama might cancel his visit.
Using mnemonics to remember the meaning of Chinese characters like can have an enormous impact on how long to learn Mandarin it takes.