Listen to the dialogues:
a)
1) ACFT: Newtown Control, KLM 301, BW at 07, FL 200, estimating DK 50; ST next.
ACC: ÊLM 301, Newtown Control, 105 kilometres from Newtown, climb to FL 230, traffic 12 o'clock, 20 km, opposite direction, at FL 240 left avoiding action.
ACFT: Climbing to FL 230, KLM 301.
ACC: Finnair 704, Newtown Control.
ACFT: Newtown Control, 704, go ahead.
ACC: Traffic 12 o'clock climbing to FL 230 20 km, opposite direction.
ACFT: Finnair 704, Roger. Looking out.
ACFT: ÊLM 301, at FL 230.
ACC: ÊLM 301, maintain FL 230 until advised.
ACFT: Maintaining FL 230, ÊLM 301.
ACC: KLM 301, now clear of traffic, climb to FL 290.
ACFT: Climbing to FL 290, ÊLM 30.
2) ACC: Angola 342, Newtown Control, identified 20 km west of Newtown. Climb to FL 210 and report. Traffic 11 o'clock, 20 km, opposite direction, at FL 240, Boeing 707.
ACFT: Climbing to FL 210, Angola 342.
ACFT: Angola 342, at FL 210.
ACC: Angola 342, climb to FL 290, 10 m/sec, report passing FL 240. Traffic 1 o'clock, 25 km, opposite direction, at FL 240 Boeing 707.
ACFT: Climbing to FL 290, 10 m/sec, will report passing FL 240.
3) ACC: Air India 216, descend to FL 220 and report, turn right 30° traffic 10 o’ clock, 12 km, in the same direction, at FL 240, Boeing 747.
ACFT: Descending to FL 220, heading 240, Air India 216.
ACC: Thainter 928, turn left 30°, traffic will be descending through your flight level.
ÀÑC: Turning left 30°, Thainter 928.
ACFT: Air India 216, at FL 220.
ACC: Air India 216, maintain FL 220 until advised.
ÀCFÒ: Maintaining FL 220, Air India 216.
ACC: Thainter 928, now clear of traffic, resume own navigation.
ACFT: Wilco, Thainter 928.
b) Listen to the dialogues again and take the controller's part.