Question

这句话有语法错误吗？

All they have to do is take a look.

Answer 1

All they have to do is to take a look.
该句中，谓语动词是is, 后面take就不能是原形啦，加上to 表即将要发生的事。 他们要做的就是去看一看。
其他地方没有问题。All they have to do中，they have to do 作定语修饰all,所以后面用的单数is.

Answer 2

正确应该是 they all have to take a look.

Answer 3

有，应该take a look at something

Answer 4

语法没有错误，但是人们通常并不这么表达。而是
instead
of
love，friend
is
what
I
need

Answer 5

remind
改为reminder；与positive
对应的应该是negative；it's改为its‘。
本句应改为：This
is reminder
that
a
formal
examination's
positive
impact
is
less
than
its
negative
one.
这是一个提醒，即正式考试的积极影响小于消极影响。