why does launch.json keep asking me which task?

  Kiến thức lập trình

I was given this tasks.json file, but but I’m seeing two problems.

    "version": "2.0.0",
    "tasks": [
            "label": "Build",
            "type": "shell",
            "command": "g++",
            "args": [
            "group": {
                "kind": "build",
                "isDefault": true
            "problemMatcher": [
  1. Every time I press command-shift-B, it asks me which one of two tasks I want to use: CMake: build, or CMake: clean rebuild. I would be happy to permanently select the first. How can I do that?

  2. same file, a second issue which may or may not be related:

build task started….
–build /Users/ken/Prog24/flgl/build –config Debug –target all —
Error: could not load cache build finished with error(s).

What does this mean, “could not load cache”? Is this some problem with a malformed tasks.json file?