Difference between lightning component and lightning web component.

1) When writing a Lightning component, you would use expression syntax {!v.attribute} when wanting to display the value.
2) When writing a lightning component, to write a condition, you would use the <aura:if> tag.
3) When writing a lightning component, to iterate over an array, you would use the <aura:iteration> tag
1) With Lightning web components, we lose the !v. part of the expression and simply add in a standard HTML Expression into the {markup}.
2) With Lightning web components, this changes to using the if:true and if:false directives to evaluate a condition.
3) With Lightning web components, this changes to using the for:each and for:item directives to iterate over an array.