Here are the hold-over usages of subjunctive that I'm aware of in English:
"If he were a doctor, he'd know what 'pneumothorax' means."
Here 'were' and 'he'd' (he would) are "past-tense" subjunctives, although they are used in a "present-tense" situation.
"If he had been a doctor, he would have known what 'pneumothorax meant." Now it's in the past tense and subjunctive. The non-standard usage of 'had been' and 'have known' indicate that they are subjunctive and are happening at the same time as the indicative verb 'meant'.
"If I were you, I wouldn't touch that electrical cable."
Here 'were' and 'wouldn't' are past-tense subjunctives used in a present-tense situation. "If I had been you, I wouldn't have touched that electrical cable." This is past tense subjunctive, most likely spoken by a bereaved friend of the departed at a funeral.
'Should', 'might', 'could', and 'would' can indicate subjunctivity; the latter two can also mean indicative action happening in the past, depending on context.
"We ask that you be quiet. We ask that he go home." 'Be' and 'go' are "present-tense" subjunctive verbs that indicate a hypothetical, desired state and, in the 2nd person, evolve into commands when shortened: "Be quiet!" "Go home!"