两词都表示 "集中，归拢"，但两者有细微区别。 

gather: 既可用于人，也可用于物。常指把零散的人或物集中，聚拢。如： 

The teacher gathered all the pupils in the auditorium.

老师把全体同学集合在礼堂内。《简明英汉词典》

The teacher went round the class to gather the papers.

老师在教室里走了一圈收试卷。《简明英汉词典》

collect: 一般只用于物，侧重指有选择或有一定计划将零散事物归拢。如： 

I've started collecting stamps.

我已开始集邮。《新牛津英汉双解大词典》

He went round the office collecting old coffee cups.

他在办公室里转来转去，把用过的咖啡杯集中起来。《新牛津英汉双解大词典》

accumulate: (gradually gather or acquire (a resulting whole))意为“积累”，有“逐步、逐渐”的含义。

Her goal was to accumulate a huge fortune.

她的目标是积累起一大笔财富。《新牛津英汉双解大词典》

练习：

C  1. _____ around the fire, the tourists danced with the local people.

     A. Gather                   B. To gather

     C. Gathering                D. To be gathering    11辽宁

D  2. Fishing is his favorite hobby, and _______.

     A. he'd like to collect coins as well

     B. he feels like collecting coins, too

     C. to collect coins is also his hobby

     D. collecting coins also gives him great pleasure    01上海

A  3. ___ energy under the earth must be released in one form or another, for example, an earthquake.

    A. Accumulated     B. Gathered     C. Assembled    D. Collected