not very effective; produce little effect的用法和樣例：
例句
- Advertisements based on these facts have been printed in newspapers and magazines but have not helped much.
根據這些情況擬定的廣告詞登載在報紙和雜志上，但是效果不大。 - If chemical thinning is not sufficiently effective, hand thinning would involve a great deal of labour.
在化學(xué)蔬果效果不大好的時(shí)候，人工疏果又牽涉到大量用工。
