安装laravel项目出错

我的本地是7.0.1，而下载下来的原来是运行在7.0.8版本的，于是执行:composer install 时，报了一堆错。解决办法：删掉composer.lock,重新composer install

  Problem 1

    - Installation request for laravel/horizon v1.0.5 -> satisfiable by laravel/horizon[v1.0.5].

    - laravel/horizon v1.0.5 requires ext-pcntl * -> the requested PHP extension pcntl is missing from your system.

  Problem 2

    - Installation request for symfony/console v3.3.10 -> satisfiable by symfony/console[v3.3.10].

    - symfony/console v3.3.10 requires php ^5.5.9|>=7.0.8 -> your PHP version (7.0.1) does not satisfy that requirement.

  Problem 3

    - Installation request for symfony/css-selector v3.3.10 -> satisfiable by symfony/css-selector[v3.3.10].

    - symfony/css-selector v3.3.10 requires php ^5.5.9|>=7.0.8 -> your PHP version (7.0.1) does not satisfy that requirement.

  Problem 4

    - Installation request for symfony/debug v3.3.10 -> satisfiable by symfony/debug[v3.3.10].

    - symfony/debug v3.3.10 requires php ^5.5.9|>=7.0.8 -> your PHP version (7.0.1) does not satisfy that requirement.

  Problem 5

    - Installation request for symfony/event-dispatcher v3.3.10 -> satisfiable by symfony/event-dispatcher[v3.3.10].

    - symfony/event-dispatcher v3.3.10 requires php ^5.5.9|>=7.0.8 -> your PHP version (7.0.1) does not satisfy that requirement.

  Problem 6

    - Installation request for symfony/finder v3.3.10 -> satisfiable by symfony/finder[v3.3.10].

    - symfony/finder v3.3.10 requires php ^5.5.9|>=7.0.8 -> your PHP version (7.0.1) does not satisfy that requirement.

  Problem 7

    - Installation request for symfony/http-foundation v3.3.10 -> satisfiable by symfony/http-foundation[v3.3.10].

    - symfony/http-foundation v3.3.10 requires php ^5.5.9|>=7.0.8 -> your PHP version (7.0.1) does not satisfy that requirement.

  Problem 8

    - Installation request for symfony/http-kernel v3.3.10 -> satisfiable by symfony/http-kernel[v3.3.10].

    - symfony/http-kernel v3.3.10 requires php ^5.5.9|>=7.0.8 -> your PHP version (7.0.1) does not satisfy that requirement.

  Problem 9

    - Installation request for symfony/process v3.3.10 -> satisfiable by symfony/process[v3.3.10].

    - symfony/process v3.3.10 requires php ^5.5.9|>=7.0.8 -> your PHP version (7.0.1) does not satisfy that requirement.

  Problem 10

    - Installation request for symfony/routing v3.3.10 -> satisfiable by symfony/routing[v3.3.10].

    - symfony/routing v3.3.10 requires php ^5.5.9|>=7.0.8 -> your PHP version (7.0.1) does not satisfy that requirement.

  Problem 11

    - Installation request for symfony/translation v3.3.10 -> satisfiable by symfony/translation[v3.3.10].

    - symfony/translation v3.3.10 requires php ^5.5.9|>=7.0.8 -> your PHP version (7.0.1) does not satisfy that requirement.

  Problem 12

    - Installation request for symfony/var-dumper v3.3.10 -> satisfiable by symfony/var-dumper[v3.3.10].

    - symfony/var-dumper v3.3.10 requires php ^5.5.9|>=7.0.8 -> your PHP version (7.0.1) does not satisfy that requirement.

  Problem 13

    - Installation request for doctrine/instantiator 1.1.0 -> satisfiable by doctrine/instantiator[1.1.0].

    - doctrine/instantiator 1.1.0 requires php ^7.1 -> your PHP version (7.0.1) does not satisfy that requirement.

  Problem 14

    - symfony/console v3.3.10 requires php ^5.5.9|>=7.0.8 -> your PHP version (7.0.1) does not satisfy that requirement.

    - psy/psysh v0.8.13 requires symfony/console ~2.3.10|^2.4.2|~3.0 -> satisfiable by symfony/console[v3.3.10].

    - Installation request for psy/psysh v0.8.13 -> satisfiable by psy/psysh[v0.8.13].

  To enable extensions, verify that they are enabled in your .ini files:

    - D:\phpStudy\php70n\php.ini

  You can also run `php --ini` inside terminal to see which files are used by PHP in CLI mode.