a="April", b="Fools" print("This is {a} {b} day")

You can use string formatting in Python to achieve this. Here's how you can do it:

```python
a = "April"
b = "Fools"

print("This is {} {} day".format(a, b))
```

However, in Python 3.6 and later, you can use f-strings for more readable and efficient string formatting:

```python
a = "April"
b = "Fools"

print(f"This is {a} {b} day")
```

Both of these methods will output:

```
This is April Fools day
```

Note that the `format()` method is more flexible and can handle more complex formatting, but f-strings are generally easier to read and use for simple cases like this.