What is a choice complex sentence is as follows:

A choice complex sentence is a sentence pattern that consists of two or more clauses, each clause expresses a possible choice or plan. These options or options are often mutually exclusive, but can also be complementary. Choice complex sentences are usually used to express one or more possible actions or results, as well as the reasons or conditions for making a choice between these actions or results.

The grammatical structure of a selected complex sentence includes two or more clauses, each clause has its own sentence components such as subject, predicate and object. In selective complex sentences, the logical relationships between clauses can be causal relationships, conditional relationships, concession relationships, hypothetical relationships, etc.

For example, the following is a causal multiple choice sentence:

Either you go to the movies, or we watch TV at home.

In this selective complex sentence, there is a causal relationship between the two clauses. The first clause expresses one choice, that is, going to the movies; the second clause expresses another choice, that is, watching TV at home. There is competition between these two options, i.e. a person can only choose one of them.

Another example, the following is a selective complex sentence of a conditional relationship:

If you come to my birthday party, I will buy you a gift.

In this selective complex sentence, there is a conditional relationship between the two clauses. The first clause is the condition, that is, you attend my birthday party; the second clause is the result, that is, I buy you a gift. If you meet the condition (attend my birthday party), you can get the result (I buy you a gift).

In short, a choice complex sentence is a sentence pattern with two or more clauses, each expressing a possible action or result. There are logical relationships between these clauses, which can be causal relationships, conditional relationships, concession relationships, hypothetical relationships, etc. Choice complex sentences are usually used to express one or more possible actions or results, as well as the reasons or conditions for making a choice between these actions or results.