Stare (intense prolonged look) vs Glance (quick brief look). Similarly Gulp (swallow large amount) vs Sip (take a small amount).

'Although' signals contrast between past certainty and present doubt. Facts once 'established' are now 'in question'.

We were surprised and pleased = the greeting was friendly (affably). Her reputation was the opposite — querulousness (irritable/complaining nature).

A metaphorical statement implies a comparison without stating it explicitly — exactly the definition of a metaphor.

First Conditional/scientific fact: if + present simple → will + base verb. 'Will' is correct.

'Mathematics' is the noun used as an adjective to modify 'teachers'. 'Mathematics teachers' is correct compound noun.

'As high as' = up to a maximum of. Standard phrase for expressing maximum value.

'Had better' + base form verb (no 'to'). 'Had better get' is correct.

Adjective + 'enough' is the correct order. 'Old enough' — not 'enough old'.

'Fail in doing something' — preposition 'in' + gerund is the correct construction.

The entire passage is about salt — its historical importance trade value and linguistic legacy.

The passage states: 'Roman soldiers transported salt crystals from the salt flats at Ostia.'

The passage directly states: 'they received a salarium or salary — literally money paid to soldiers to buy salt.'

The passage states 'worth their salt' means 'to be valuable' — a valuable employee.

'my student' is an appositive phrase — must be set off by commas on both sides.

'Inimical' = hostile/unfriendly. Antonym: 'Friendly'.

'Efface' = to erase. 'Rub out' = to erase/remove — best synonym.

Present Simple Negative passive: object becomes subject + are not liked + by us.

'The' before river names and before superlatives. 'Africa' needs no article.

'Andrea del Sarto' is a famous dramatic monologue by Robert Browning. Scholar Gipsy = Matthew Arnold.