From Longman Dictionary of Contemporary Englishbe plain sailingbe plain sailingEASYto be very easy to do or achieve If you can answer the first question, the rest of the test should be plain sailing. → plain
Examples from the Corpus
be plain sailing• Get the mitres right and the rest is plain sailing.• I recognized that all would not be plain sailing.• In any event, it will not be plain sailing.• Roderick Conway Morris says it's not going to be plain sailing. 