4. Use of prepositions

In British English, at is used with many time expressions, e.g.:

at Christmas/five 'o' clock

at the weekend

In American English, on is always used when talking about the weekend, not at, e.g.:

Will they still be there on the weekend?

She'll be coming home on weekends.

In British English, at is often used when talking about universities or other institutions, e.g.:

She studied chemistry at university.

In American English, in is often used, e.g.:

She studied French in high school.

In British English, to and from are used with the adjective different, e.g.:

This place is different from/to anything I've seen before.

In American English from and than are used with different, e.g.:

This place is different from/than anything I've seen before.

In British English to is always used after the verb write, e.g.:

I promised to write to her every day.

In American English, to can be omitted after write, i.e.:

I promised to write her every day.

5. Past tense forms

Below is a table showing verbs which have different simple past and past participle forms in American and British English. Note that the irregular past forms burnt, dreamt and spoilt are possible in American English, but less common than the forms ending in -ed.

Infinitive	Simple past (Br)	Simple past (Am)	Past participle (Br)	Past participle (Am)
burn	burned/ burnt	burned/ burnt	burned/ burnt	burned/ burnt
bust	bust	busted	bust	busted
dive	dived	dove/ dived	dived	dived
dream	dreamed/ dreamt	dreamed/ dreamt	dreamed/ dreamt	dreamed/ dreamt
get	got	got	got	gotten
lean	leaned/ leant	leaned	leaned/ leant	leaned
learn	learned/ learnt	learned	learned/ learnt	learned
plead	pleaded	pleaded/ pled	pleaded	pleaded/ pled
prove	proved	proved	proved	proved/ proven
saw	sawed	sawed	sawn	sawn/ sawed
smell	smelled/ smelt	smelled	smelled/ smelt	smelled
spill	spilled/ spilt	spilled	spilled/ spilt	spilled
spoil	spoiled/ spoilt	spoiled/ spoilt	spoiled/ spoilt	spoiled/ spoilt
stink	stank	stank/ stunk	stunk	stunk
wake	woke	woke/ waked	woken	woken

Note that have got is possible in American English, but is used with the meaning 'have', gotten is the usual past participle of get, e.g.

American English	British English
You've got two brothers (= you have two brothers)	You've got two brothers
You've gotten taller this year	You've got taller this year