effectiveness and efficient 一問

Effective 解做事達到目的 (做啱咗)；efficient 解做事有效率(做得快)。

Example:

Trams and ferries are inexpensive and effective means of transportation in Hong Kong, but they are taking too long, so are not as efficient as the metro.

the new messenger is very efficient；he usually gets the delivery done faster than others, but he also makes delivery errors quite often, so is not that effective.