1.

You observe that someone is approaching from the opposite direction.

towards

2.

You both halt and exchange apologetic smiles.

each other

3.

That we are aware of its importance can be gauged from the significance parents attach to a baby's first steps.

know how

4.

With the exception of talking, no other developmental landmark is so eagerly awaited.

only

5.

They filmed four hours' activity on one such crossing.

kind

6.

Women turn their backs on them, regardless of their own age and the age of the other person.

however

7.

In the next few years we must expect to hear a lot more about walking.

likely

8.

We must expect to hear a lot more about walking from psychologists and sociologists.

tell

9.

It will sound so complicated a skill that many of us will hesitate to set foot outside our front doors.

such

10.

This won't deter the five million Britons who treat walking as a recreation.

put  /  think