xuǎnzé xǐyīchéngxù yǐhòu, xǐyījī kāishǐ tuōshuǐ.

The sentence breaks into two main parts:

选择洗衣程序以后 = after selecting the washing program
洗衣机开始脱水 = the washing machine starts spin-drying

So the structure is:

[time/event clause] + [main clause]

This is a very common Chinese pattern: [something happens] 以后, [something else happens]

When 以后 means after, it usually comes after the action or event it refers to.

So:

• 选择洗衣程序以后 = after selecting the washing program

This is different from English, where after usually comes before the action:

• English: after selecting the washing program
• Chinese: select washing program + after

Common pattern:

• 吃饭以后 = after eating
• 下课以后 = after class ends
• 回家以后 = after going home

Yes. 以后 and 后 can both mean after in this kind of sentence.

So these are both natural:

• 选择洗衣程序以后，洗衣机开始脱水。
• 选择洗衣程序后，洗衣机开始脱水。

以后 can sound a little more complete or slightly more formal in some contexts, but the difference here is small.

Be careful, though: 以后 can also mean later or in the future in other contexts, such as:

• 以后再说。 = We’ll talk about it later.
• 我以后想去中国。 = I want to go to China in the future.

Here, because it follows an action, it clearly means after.

Chinese often omits a subject when it is obvious from context.

In this sentence, the person doing 选择洗衣程序 is understood to be the user / you / someone operating the machine. Chinese does not need to say that explicitly if the meaning is clear.

A more expanded version could be:

• 你选择洗衣程序以后，洗衣机开始脱水。

But in instructions or descriptions, leaving out 你 is very common and sounds natural.

The comma separates the introductory time phrase from the main clause.

So:

• 选择洗衣程序以后， = after selecting the washing program,
• 洗衣机开始脱水。 = the washing machine starts spin-drying.

In English, this is similar to writing:

• After selecting the washing program, the washing machine starts spin-drying.

In Chinese writing, this comma is very common when a time phrase or condition comes first. In very short sentences, punctuation can sometimes vary, but here the comma is natural and standard.

开始 means to begin / to start, and it can be followed directly by a verb or verb phrase.

So:

• 开始脱水 = start spin-drying
• literally: begin + remove water

Chinese does not need a word like English to here.

Compare:

• 开始洗衣 = start washing clothes
• 开始工作 = start working
• 开始学习 = start studying

So 开始脱水 is a normal 开始 + verb structure.

In this sentence, 脱水 refers to the washing machine’s spin-dry / spin cycle function: removing water from clothes.

Literally:

• 脱 = remove / take off / get rid of
• 水 = water

So 脱水 literally means remove water.

Important: in everyday Chinese, 脱水 can also mean dehydration in a medical sense, depending on context. But with a washing machine, it clearly means spin-drying or spinning out the water.

Chinese often puts one noun or verb-like modifier directly before another noun, without 的, especially in compact expressions and technical terms.

So:

• 洗衣程序 = washing program / wash cycle

Here, 洗衣 modifies 程序 directly.

Using 的 is not impossible in all situations, but 洗衣程序 is more natural, concise, and typical for appliance language, labels, and instructions.

This kind of compact modifier structure is very common:

• 手机屏幕 = phone screen
• 电脑软件 = computer software
• 洗衣机门 = washing machine door

Yes, you often can.

• 选 = choose, select
• 选择 = choose, select

选择 is a bit more formal or polished, so it fits written instructions well. 选 is more casual and common in everyday speech.

So:

• 选择洗衣程序以后 sounds natural in written or instructional language.
• 选洗衣程序以后 is understandable and more conversational.

In product instructions, 选择 is especially common.

Because the sentence is describing a process or sequence in a neutral way, not emphasizing completion or a new situation.

Without 了, the sentence reads like a general statement or instruction:

• 选择洗衣程序以后，洗衣机开始脱水。

If you wanted to describe a specific event that has actually happened, you might add 了:

• 选择洗衣程序以后，洗衣机就开始脱水了。

That version feels more like: After the program was selected, the machine started spin-drying.

So the version without 了 is very normal for explanations, manuals, and general descriptions.

It can be, depending on context.

程序 has a broader meaning than English program in the computer-only sense. It can mean:

• a program
• a procedure
• a process
• a set operating cycle

In 洗衣程序, it means the machine’s wash program / cycle setting, not a computer program in the usual English sense.

So 程序 is a flexible word whose exact meaning depends on context.

Yes. It is very typical.

Chinese often puts time expressions or conditions first, then the main statement after that.

So this order is very natural:

• 选择洗衣程序以后，洗衣机开始脱水。

That is:

1. first event: select the program
2. main event: the machine starts spin-drying

This kind of order is extremely common in Chinese:

• 吃完饭以后，我去上班。 = After eating, I go to work.
• 下雨以后，天气凉快了。 = After it rains, the weather becomes cooler.

So the sentence follows a very standard Chinese pattern.