BEGIN, START, COMMENCE, INITIATE, INAUGURATE, USHER IN mean to take the first step in a course, process, or operation.

BEGIN, START, and COMMENCE are often interchangeable.

begin

开始；开始进行（或存在）

to do the first part of an action : go into the first part of a process

BEGIN, opposed to end, is the most general.

// begin a trip 开始旅行

// begin dancing 开始跳舞

// [ + -ing verb ] Jane has just begun learning to drive. 珍妮刚开始学开车。

// [ + to infinitive ] After waiting for half an hour she was beginning to get angry. 等了半小时后，她开始生气了。

// If you want to learn to play a musical instrument, it might be a good idea to begin on something simple. 如果你想学一种乐器，从简单的开始或许是个好主意。

start

开始；着手

START, opposed to stop, applies especially to first actions, steps, or stages.

// When do you start your course/your new job? 你什么时候开始你的课程／新工作？

// Do you start (= begin a new job) on Monday? 星期一你开始工作吗？

// [ + -ing verb ] They started building the house in January. 他们1月份动工盖这所房子。

// [ + to infinitive ] I'd just started to write a letter when the phone rang. 我刚开始写信，电话铃就响了。

** [ I ] informal to begin to complain or be annoying in some way 开始抱怨；开始惹人厌烦

// Don't start with me - we're not going and that's that! 别烦人——我们不去，没的商量！

// informal "It would help if Richard did some work." "Oh, don't get me started on Richard!" “如果理查德做了些工作就好了。”“噢，别提理查德了，说起他来我就生气！”

commence

开始；着手

COMMENCE can be more formal or bookish than BEGIN or START.

// commence a conversation 开始对话

// Shall we let the meeting commence? 我们开始开会，好吗？

// [ + -ing verb ] commence firing 开始射击/开火

// Unfortunately, he commenced speaking before all the guests had finished eating. 遗憾的是，没等所有客人都吃完，他就开始讲话了。

// The industry’s major job cuts are expected to commence Oct. 1, roughly a month before the U.S. presidential election.

— Justin Bachman, Fortune, "United Airlines tells nearly half its staff they could lose their jobs this autumn," 9 July 2020

initiate

开始，创始

INITIATE implies taking a first step in a process or series that is to continue.

// initiate diplomatic contacts 开始外交接触

// initiate a program of reform 启动改革方案

// The company initiated judicial proceedings against them. 该公司对他们提起了司法诉讼。

// Doctors have initiated a series of tests to determine the cause of the problem. 医生已经开始了一系列测试以确定问题原因。

inaugurate

（正式）启用，启动

INAUGURATE suggests a beginning of some formality or notion of significance.

// the discovery of penicillin inaugurated a new era in medicine 青霉素的发现开创了医学的新纪元

// Italian Prime Minister Giuseppe Conte was due Monday to inaugurate the new bridge, which was designed by star architect Renzo Piano and was built in little more than a year. ...

— Eric Sylvers, WSJ, "Italy to Open New Bridge, Two Years After Deadly Collapse," 3 Aug. 2020

usher in

开创（尤指重大的变化或新事物）；开始；开启

to be at the start of a new period, especially when important changes or new things happen, or to cause important changes to start happening

USHER IN is somewhat less weighty than INAUGURATE.

// ushered in a period of economic decline 开始了经济下滑时期

// These changes could usher in a period of dramatic economic growth. 这些改变有可能开启一个经济急剧增长的时期。

begin, start, commence, initiate, inaugurate, usher in